Para mi depende mucho de los datos que vas a cargar también.
Si los datos, aunque son muchos (40 como decis) no tienen mucha relación entre si, y el operador no tiene que visualizar todos los datos como control para la carga de los mismo, creo que la opción de João es la más apropiada.
En cambio, si lo más apropiado es que el operador vea todos los datos que está cargando por una cuestión de control, y dichos datos no son todos alfanuméricos largos, otra opción podría ser un solo formulario con GROUP para agrupar los datos relacionados, y los GETS que sean largos codificarlos con scroll (PICTURE "@S25" por ej.), y hacerlo a lo ancho de la pantalla, con el TAB INDEX (si lo haces por recursos) de arriba hacia abajo y de izquierda a derecha.
CLIENTES DIALOG DISCARDABLE 6, 18, 534, 346
STYLE WS_POPUP|DS_MODALFRAME|WS_CAPTION|WS_SYSMENU|WS_VISIBLE
CAPTION "Ficha de cliente"
FONT 8, "Tahoma"
{
CONTROL "Datos Personales", -1, "Button", BS_GROUPBOX, 4, 4, 264, 92
CONTROL "Codigo:", -1, "Static", SS_RIGHT|WS_GROUP, 16, 20, 28, 8
CONTROL "", 100, "Edit", ES_RIGHT|ES_AUTOHSCROLL|WS_BORDER|WS_TABSTOP, 48, 16, 44, 12
CONTROL "Alias:", -1, "Static", SS_RIGHT|WS_GROUP, 96, 20, 20, 8
CONTROL "", 101, "Edit", ES_AUTOHSCROLL|WS_BORDER|WS_TABSTOP, 120, 16, 72, 12
CONTROL "Nombre:", -1, "Static", SS_RIGHT|WS_GROUP, 12, 36, 32, 8
CONTROL "", 102, "Edit", ES_AUTOHSCROLL|WS_BORDER|WS_TABSTOP, 48, 32, 216, 12
CONTROL "C.U.I.T.:", -1, "Static", SS_RIGHT|WS_GROUP, 12, 52, 32, 8
CONTROL "", 103, "Edit", ES_AUTOHSCROLL|WS_BORDER|WS_TABSTOP, 48, 48, 68, 12
CONTROL "D.N.I:", -1, "Static", SS_RIGHT|WS_GROUP, 152, 52, 24, 8
CONTROL "", 104, "Edit", ES_RIGHT|ES_AUTOHSCROLL|WS_BORDER|WS_TABSTOP, 180, 48, 84, 12
CONTROL "Telefonos:", -1, "Static", SS_RIGHT|WS_GROUP, 8, 68, 36, 8
CONTROL "", 105, "Edit", ES_MULTILINE|ES_AUTOHSCROLL|ES_AUTOVSCROLL|WS_BORDER|WS_TABSTOP, 48, 64, 216, 12
CONTROL "Mail:", -1, "Static", SS_RIGHT|WS_GROUP, 8, 84, 36, 8
CONTROL "", 106, "Edit", ES_MULTILINE|ES_AUTOHSCROLL|WS_BORDER|WS_TABSTOP, 48, 80, 216, 12
CONTROL "Datos generales", -1, "Button", BS_GROUPBOX, 272, 4, 260, 76
CONTROL "Localidad:", -1, "Static", SS_RIGHT|WS_GROUP, 284, 20, 32, 8
CONTROL "", 107, "Edit", ES_AUTOHSCROLL|WS_BORDER|WS_TABSTOP, 320, 16, 208, 12
CONTROL "Cod. Postal:", -1, "Static", SS_RIGHT|WS_GROUP, 276, 36, 40, 8
CONTROL "", 108, "Edit", ES_RIGHT|ES_AUTOHSCROLL|WS_BORDER|WS_TABSTOP, 320, 32, 44, 12
CONTROL "Barrio:", -1, "Static", SS_RIGHT|WS_GROUP, 292, 52, 24, 8
CONTROL "", 109, "Edit", ES_AUTOHSCROLL|WS_BORDER|WS_TABSTOP, 320, 48, 208, 12
CONTROL "Direccion:", -1, "Static", SS_RIGHT|WS_GROUP, 284, 68, 32, 8
CONTROL "", 110, "Edit", ES_AUTOHSCROLL|WS_BORDER|WS_TABSTOP, 320, 64, 208, 12
CONTROL "Datos Impositivos", -1, "Button", BS_GROUPBOX, 4, 96, 264, 92
CONTROL "Condicion IVA:", -1, "Static", SS_RIGHT|WS_GROUP, 12, 112, 48, 8
CONTROL "", 111, "ComboBox", WS_BORDER|CBS_DROPDOWNLIST|WS_VSCROLL|WS_TABSTOP, 64, 108, 200, 40
CONTROL "% Descuento:", -1, "Static", SS_RIGHT|WS_GROUP, 12, 128, 48, 8
CONTROL "", 112, "Edit", ES_RIGHT|ES_AUTOHSCROLL|WS_BORDER|WS_TABSTOP, 64, 124, 44, 12
CONTROL "Comprobantes:", -1, "Static", SS_RIGHT|WS_GROUP, 112, 128, 52, 8
CONTROL "", 113, "ComboBox", WS_BORDER|CBS_DROPDOWNLIST|CBS_SORT|WS_VSCROLL|WS_TABSTOP, 168, 124, 96, 40
CONTROL "Vendedor:", -1, "Static", SS_RIGHT|WS_GROUP, 12, 144, 48, 8
CONTROL "", 114, "Edit", ES_RIGHT|ES_AUTOHSCROLL|WS_BORDER|WS_TABSTOP, 64, 140, 44, 12
CONTROL "", 115, "Edit", ES_AUTOHSCROLL|WS_BORDER|WS_TABSTOP, 112, 140, 152, 12
CONTROL "Tabla desc.:", -1, "Static", SS_RIGHT|WS_GROUP, 12, 160, 48, 8
CONTROL "", 129, "Edit", ES_RIGHT|ES_AUTOHSCROLL|WS_BORDER|WS_TABSTOP, 64, 156, 44, 12
CONTROL "", 130, "Edit", ES_AUTOHSCROLL|WS_BORDER|WS_TABSTOP, 112, 156, 152, 12
CONTROL "% II.BB.:", -1, "Static", SS_RIGHT|WS_GROUP, 32, 176, 32, 8
CONTROL "", 126, "Edit", ES_RIGHT|ES_AUTOHSCROLL|WS_BORDER|WS_TABSTOP, 64, 172, 28, 12
CONTROL "Saldo:", -1, "Static", SS_RIGHT|WS_GROUP, 92, 176, 24, 8
CONTROL "", 127, "Edit", ES_RIGHT|ES_AUTOHSCROLL|WS_BORDER|WS_TABSTOP, 120, 172, 40, 12
CONTROL "Saldo Demo:", 4001, "Static", SS_RIGHT|WS_GROUP, 164, 176, 44, 8
CONTROL "", 128, "Edit", ES_RIGHT|ES_AUTOHSCROLL|WS_BORDER|WS_TABSTOP, 212, 172, 40, 12
CONTROL "Datos del transporte:", -1, "Button", BS_GROUPBOX, 272, 80, 260, 76
CONTROL "Transporte:", -1, "Static", SS_RIGHT|WS_GROUP, 276, 96, 40, 8
CONTROL "", 116, "Edit", ES_RIGHT|ES_AUTOHSCROLL|WS_BORDER|WS_TABSTOP, 320, 92, 44, 12
CONTROL "", 117, "Edit", ES_AUTOHSCROLL|WS_BORDER|WS_TABSTOP, 368, 92, 160, 12
CONTROL "Localidad:", -1, "Static", SS_RIGHT|WS_GROUP, 284, 112, 32, 8
CONTROL "", 118, "Edit", ES_AUTOHSCROLL|WS_BORDER|WS_TABSTOP, 320, 108, 208, 12
CONTROL "Direccion:", -1, "Static", SS_RIGHT|WS_GROUP, 284, 128, 32, 8
CONTROL "", 119, "Edit", ES_AUTOHSCROLL|WS_BORDER|WS_TABSTOP, 320, 124, 208, 12
CONTROL "Telefono:", -1, "Static", SS_RIGHT|WS_GROUP, 284, 144, 32, 8
CONTROL "", 120, "Edit", ES_AUTOHSCROLL|WS_BORDER|WS_TABSTOP, 320, 140, 208, 12
CONTROL "Datos de contacto", -1, "Button", BS_GROUPBOX, 4, 188, 264, 60
CONTROL "Nombre:", -1, "Static", SS_RIGHT|WS_GROUP, 12, 200, 32, 8
CONTROL "", 121, "Edit", ES_AUTOHSCROLL|WS_BORDER|WS_TABSTOP, 48, 200, 216, 12
CONTROL "Telefonos:", -1, "Static", SS_RIGHT|WS_GROUP, 8, 216, 36, 8
CONTROL "", 122, "Edit", ES_MULTILINE|ES_AUTOHSCROLL|WS_BORDER|WS_TABSTOP, 48, 216, 216, 12
CONTROL "Mail:", -1, "Static", SS_RIGHT|WS_GROUP, 8, 232, 36, 8
CONTROL "", 123, "Edit", ES_MULTILINE|ES_AUTOHSCROLL|WS_BORDER|WS_TABSTOP, 48, 232, 216, 12
CONTROL "Datos de entrega", -1, "Button", BS_GROUPBOX, 272, 156, 260, 92
CONTROL "Nombre:", -1, "Static", SS_RIGHT|WS_GROUP, 280, 172, 32, 8
CONTROL "", 4004, "Edit", ES_AUTOHSCROLL|WS_BORDER|WS_TABSTOP, 316, 168, 212, 12
CONTROL "Localidad:", -1, "Static", SS_RIGHT|WS_GROUP, 280, 188, 32, 8
CONTROL "", 4005, "Edit", ES_AUTOHSCROLL|WS_BORDER|WS_TABSTOP, 316, 184, 212, 12
CONTROL "Direccion:", -1, "Static", SS_RIGHT|WS_GROUP, 276, 204, 36, 8
CONTROL "", 4006, "Edit", ES_MULTILINE|ES_AUTOHSCROLL|WS_BORDER|WS_TABSTOP, 316, 200, 212, 12
CONTROL "Telefonos:", -1, "Static", SS_RIGHT|WS_GROUP, 276, 220, 36, 8
CONTROL "", 4007, "Edit", ES_MULTILINE|ES_AUTOHSCROLL|ES_AUTOVSCROLL|WS_BORDER|WS_TABSTOP, 316, 216, 212, 12
CONTROL "Horario:", -1, "Static", SS_RIGHT|WS_GROUP, 276, 236, 36, 8
CONTROL "", 4008, "Edit", ES_MULTILINE|ES_AUTOHSCROLL|WS_BORDER|WS_TABSTOP, 316, 232, 212, 12
CONTROL "Observaciones:", -1, "Button", BS_GROUPBOX, 4, 248, 260, 68
CONTROL "", 125, "Edit", ES_AUTOHSCROLL|WS_BORDER|WS_TABSTOP, 8, 256, 252, 56
CONTROL "Impresion", -1, "Button", BS_GROUPBOX, 272, 248, 260, 68
CONTROL "", 124, "Edit", ES_MULTILINE|ES_AUTOHSCROLL|WS_BORDER|WS_TABSTOP, 276, 256, 224, 56
CONTROL "0", 200, "Button", BS_AUTORADIOBUTTON, 504, 256, 20, 10
CONTROL "25", 201, "Button", BS_AUTORADIOBUTTON, 504, 268, 24, 10
CONTROL "50", 202, "Button", BS_AUTORADIOBUTTON, 504, 280, 20, 10
CONTROL "75", 203, "Button", BS_AUTORADIOBUTTON, 504, 292, 20, 10
CONTROL "100", 204, "Button", BS_AUTORADIOBUTTON, 504, 304, 24, 10
CONTROL "&Aceptar", 301, "Button", WS_TABSTOP, 144, 332, 50, 14
CONTROL "&Cancelar", 302, "Button", WS_TABSTOP, 344, 332, 50, 14
CONTROL "I.V.A Exento", 401, "Button", BS_AUTOCHECKBOX|WS_TABSTOP, 212, 16, 52, 10
CONTROL "F.de Crédito", 4002, "Button", BS_AUTOCHECKBOX|WS_TABSTOP, 4, 316, 52, 10
CONTROL "Dias Vto::", -1, "Static", SS_RIGHT|WS_GROUP, 60, 316, 40, 8
CONTROL "", 4003, "Edit", ES_RIGHT|ES_AUTOHSCROLL|WS_BORDER|WS_TABSTOP, 100, 314, 28, 12
CONTROL "Lista de Precios base:", -1, "Static", SS_RIGHT|WS_GROUP, 320, 320, 108, 8
CONTROL "", 4009, "ComboBox", WS_BORDER|CBS_DROPDOWNLIST|CBS_SORT|WS_VSCROLL|WS_TABSTOP, 432, 316, 96, 40
}