very purdy. Saves you a bit of copper it would seem and having to wrench around HV. Trust me working with nuts and bolts when you have 100V+ potential under your gloves doesn't instill confidence! This design you just have to slip the bullet connectors in place
Also think about how you will assembly it. Will you have enough room to plug each bullet connector in to the appropriate busbar... Maybe mess around with some cardboard/wood and the batteries to see how easy/hard it is to twist and plug them in where you need them. Since you have the space it may work well to have each 8p be a separate box with separate busbar and a jumper across them.
It could also be useful to put a nice big connector/terminal block to disconnect the top back from the bottom which would allow you to have two lower voltage packs when working on it.
It's looking good!