I can weld, I'm not worried about that.
I would like something extra at the miter joints, due to the 500+ hp motor going in it.
Believe me, I don't baby anything, so it needs to be safe.

I like the internal gusset, same as sleeving a tube joint IMO
However I still have this nagging need to understand fully a gussets job, how it werkz, and how to determine the proper application for a gusset, size, material, thickness % etc.

sometimes I have these voices in my head that don't shut up until they get an answer lol