Why not go one step further on the logical scale: make a new module that works like the SRV bays and can hold multiple sub modules.
Now just make that one not skip odd sizes (bays go 2 4 6 8 10) and make it hold computer control modules.
So you can fit both S1's into a S2+ version of this container module.
Btw, I made this (what I just wrote) suggestion already years ago, but maybe it will be heard this time. Hope dies last after all.