Good thread - it's nice to see some builds where people had to do serious work to the infrastructure before tackling the theatre aspect! I can empathize since I ended up taking the entire pad out of my basement (90,000lbs of concrete broken via hammer and carried up the stairs

), steel-braced all the walls, and redid the entire electrical, plumbing, and HVAC. That sort of killed the theatre budget, and I've been on hold for a while.
Can you tell me exactly which Sakrete product you used? Was it self-levelling? We poured the new pad ourselves, and had a buddy power trowel it, but there's a couple of spots that I need to level out.