The day before yesterday, I wrenched my back while finishing on the hanger construction. I was put out of commision for the remainder of the day and yesterday. Today, I completed it. My back is much better now. This myriad of injuries is annoying, but I'm impressed by my body's resilience in recovering.
I hung the heavy bag and the situation is worlds better than before. I can actually move around it and get in close now. The speed-bag swivel was shoddily designed, however. The hook is mechanically closed. Every speed bag that I have seen ends in a closed loop, and it's impossible to hang up the two that I already have. I'm going to disassemble the swivel mechanism from the other platform that I purchased a few years ago and apply it to the new one.
My knee almost gave out today mid-squat as I was lifting up the heavy bag to hang. I redeemed myself a few hours later by doing it with no pain, although I was careful not to shift as much weight on the problematic knee. My ankle on that same leg has also been in pain for the last couple of days for reasons unbeknownst to me. The road to redemption from here is long, but that's what makes greatness what it is.
Edit: my lingering ankle pain has completely subsided in a matter of hours. I know I'm great, but now I can't even control it.