How much extra space do I need?

I’m trying to figure out if the 12s2p will fit nicely in my setup. The manufacture says it’s 28cm. I have about 30cm, but I’m anticipating the need for more space for wires, bms, charging plug, etc.

Image uploads are not currently working for me so here’s the link: IMG 20240505 223010 113 — Postimages

What’s you guys’ opinion? Also, Is the bms on top of the esc okay? It’s in a well insulated (rubber) casing. I’m planning to put a big heat sink on the other side of the esc, so it should stay nice and cool.

Other option is the 10s2p. Which is only 24 cm which will allows for a lot of extra space, but obviously less power. I’m not looking to go super fast just need the low end torque to get up hills, but a well built and longer lasting board is a must. In the past my 12s setup was pretty good, but still could not get me up a steep hill from dead stop. Would the 7V difference make a large impact on low end torque?

Image uploads are not currently working for me so here’s the link.