I thought I had pics of the buss bar cut, but I can't find them. Next time I have the battery rolled away from the wall, I will try to pop off the cover for a pic, but I also coated the cut area with liquid electrical tape. Man that stuff smells bad when you spread it on.
I never actually split apart the brick. That would likely require the rivets to be removed to allow the buss bar to slide apart as you split between the cells. The odd issue also comes in with the cells being packed as pairs, but wired in triples. Trying to pull off a 4S chunk should work. 4S-3P is 12 cells, so that would be six 2 packs. Then you just have to splice that on the end of the 10S-3P 30 pack, 15 pairs. Total 42 cells = 14S-3P
My big fear on the solar panel placement would be someone putting a ladder up, climbing onto may garage roof, and stepping right on the panels, as they are not really going to be visible from the ground. My current panels up the sloped roof are very obvious. They might not expect there to be 6 more flat on the garage. I do plan on adding the layout over by the disconnect, but that may be too late. They will see the 16 up on the roof and not take the time to see there is another group. So I want 3 feet all the way around the array so as anyone gets on the roof, it is obvious when they get up there. The more I am looking at it though, I think I am going to just skip the rails, and use "Z" brackets to just bolt the panels down to the concrete blocks. This puts the panels much lower to the garage flat roof. That vastly lowers the wind loading as well. Almost no wind will be able to get under them. With the same 20 concrete blocks, each panel will be clamped to 6 blocks. It would take a serious tornado to move them. The edges of the solar panels will only be 2 inches off the existing roofing between the concrete blocks. The ground wire will need to zig zag between the 6 panels and have 6 separate lugs, since they won't be clamped to metal. I will also bolt the Tigo RSD boxes to the concrete blocks under the panels. I have to see if I can use PVC conduit, or if it needs to be in heavy wall metal pipe. I can do either, but the PVC is much easier to deal with.