trying to fit cosworth disks onto a xr4x4 uprights.

bought the conversion kit to space out the calipers and some new cos 4x4 disks but the disk offset is not correct

maybe i need 2wd disks? - the face of the xr4x4 disk is inset 28.5mm from the wheel mounting face on the disk, anyone know if this the same as 2wd cos disks, or what the distance is on 2wd disks