The board adds 4 identical banks of 16MB, and duplicates the bank0 set currently present on a MK2A. Obviously, this isn't going to work all that well. The idea is that each bank can be disabled by means of a switch on the memory board, so in the case of a MK2A you would turn off the first bank. This would still give you 64M, as the original memory would be used.

As for room, there's a whole 2.5-3mm available! 0.8mm for the PCB, 1.2mm for the chips, 0.1mm for the insulator sheet on each side of the PCB, and loads of room left over

pca