Yep, sounds like you have way more experience than me - this is my first pack - I think I'll just buy the $250 48v AIMS inverter to test with and then sell it on Craigslist once I'm done -I've posted at link below what my plan is for capacity testing:
With these high-capacity battery packs, I think it's definitely worth it to have a way to put bulk energy in and out.
Disassembling and reassembling everything is a hassle, but hopefully it only has to be done once or twice. (If you think the balance is close enough, you might even get away with just letting the BMS balance the cells, so zero re-wires.)