iv done something similar with a nyx frame, 22s18p30Qpack, max-e 14kw, qs205 w/6wag upgraded phases.
i had the controller internal, with similar 12p pack,and used fan in seatpost to remove controller heat, but after upsizing the pack, only the dc/dc, charger coil, and bms fit in with the cells, i ditched the fan and put the controller out in the wind.
the fan was very effective when i had it though.
w/ regards to pack support in frame, iv decided to hotglue it in once its past the mockup stage, w/good quality hotglue(bosch brand)
since i discovered that metholated spirit will very effectively remove hotglue, im not scared to spread it about in the frame
i also love the shinko 241s and have a pair, but not sure if i should use them over the slicker tyres i have due to decrease in efficiency, as tradeoff for the absolutely awesome traction they will have. any info on this?
i currently use a hydenau M3, 2,1/4"/19" on the front. looks like your front tyre there. iv been so impressed w/this tyre so far, really silent/efficient but had heaps of grip.
i have a eltek flatpack s on my wishlist
I must admit im now very interested in your 24fet controller as adapttos are too expensive, tend to fail and are too expensive to repair.
the only features id really miss are the battery cell monitor screen and the charging through controller w/coil, but i could live without these, id rather something powerful and simple/silent compact that is more reliable.