Tom the problem is that the 7750 that have different configurations i.e. instead of 6,9,12 all have longer subdial stems (not sure of the correct terminology) to accommodate the module for the transfer of gears from 12 oclock position to the 3 oclock position.
What this means is, if you try and put the module mentioned above onto a standard 6,9,12 7750 the subdial stems at 9 oclock and 6 oclock will be too short, and when the dial is placed on top of the movement the sub dial stems, dont 'stick out' far enough to attach the sub dial hands.
so unfortunately its a no go. you can over come it by replacing the sub dial stems fro the 3,6,9 movement to the 6,9,12 movement but its a big job and both movements need stripping.
The only other option is to source a 212 movement or 3,6,9 movement.
Hope this helps