I edited one of my early posts in this build thread. I renamed it a quick review. At the bottom I had a comment about the battery space that I have now moved here.
"I'm fairly certain that the 16S, 26Ah battery minus that space wasting plastic box can hold 20S and 26Ah. I'm sure going to try to make it fit!"
I think that's great! I forgot all about writing this. AND I've exceeded that by 20Ah!