you can fold them up so the cells are all next to each other and the metal strips are flat! on the top of each photo is the old pack, and on the bottom are the new cells arranged with the correct polarity and taped together.
i also used superglue to hold rows of cells together, but in hindsight it might have been better to make a 3D printed jig to hold them.
i've welded new metal tabs onto the cells, following the pattern of the old ones. here's one of the two inline fuses that i pulled off the other pack. the other one is already welded in place.