I’ve decided to not go with a 12s6p NESE. See the discussion in my other build-thread about the arcing issues I’ve experienced:
Also, some of the salvaged 40T cells I bought from Nkon have physical dents / bulges on the negative terminals. So I don’t have enough cells for 12s6p + 12s3p for my brother + 12s4p for @RDs . The box I’m using is large enough for a vertically-oriented 12s7p, or for 2 rows of stagger-stacked 12s4p batteries. Now, I have enough good cells for RDs’s 12s4p and for a 12s8p, so I think that’s what I’ll go for.
Question is – do I connect these 2 4P rows as a single 12s8P battery, or as 2x 12s4p batteries with their own BMS? Having 2 smaller batteries sounds nice, because then I could just remove one if I want to decrease weight for jumping 
On the other hand, I’d need to charge them separately, and that could be quite annoying… What do people think?