Note that PW has very little on his harness, is wearing long pants (hefty long pants), and is hauling his stuff. The knee pads are a bit flip, but some folks put thin pads under their pants or just bandage their knees before.
We can't see into the upper crack, so maybe it has flaring nasty walls and is not too deep at top. The bottom looks easy. Geez, I hope the pics in your TR will not be all fisheye views! Is that a chockstone blocking the top? That could be your biggest problem, but also the easiest place to put protection.
As a non-climber, my biggest mistake is getting caught up on pack/gear in a chimney.