I also tried what the lowest tooth count you can fit were.
Totaly 64 tooths, 17/47 Mod 1.0 was the absolutley smalles I managed to fit, and then I even had to remove a tiny bit of material from the gearbox! And this was with the 2350motor wich doesnīt have the finns as the 2200kv has, 64tooths wouldnīt be enough for the 2200kv to mesh properly.:
A tiny amount of material removed
I finnaly got my new aluminum bulkhead braces! But when I deassembled everything I found this

:
I just bent it back, same thing in the front as well as in the rear:
Maybe it had something to do with this

: