Cut out all the cloth, and refilled my 2" tape box.
Trimmed and taped the seatback opening above the heat duct, not in the plans specifically, but seemed like it should be done.
Applied 4 x BID / 3 x UNI reinforcement to center seatbelt mounting point. Tried to do it on the bench and transfer it, but it wouldn't follow the profile. Applied 2 plies at a time, which worked much better.
Was able to reuse the first attempt after peeling it off and stripping it apart, the UNI helped hold it together. If it was all BID I'd have thown it away.