Wow, what a wonderful project, congratulations.
I have recently been repairing a vintage SOL-20 computer from 1976 and it is amazing what they could do. The one I have is fitted with three 16k memory cards.
What astonished me was the number of IC's that Processor Technology (PT) used to create a 16k S-100 style memory card. About 71 IC's . That is more than the total number of IC's used in Atari's Arcade Pong video game from 1972, which has 66 TTL's, for a whole video game.
These old PT cards are really worth a look, they also contained digital delay lines, there is a photo of them here:
http://worldphaco.com/uploads/PROCES...A_RAM_CARD.pdf