Only the sides and bottom skins are riveted on the aft fuselage at this point and the top is just in with clecos. Removing it will make the 4-point harness work much easier, so we did. We had to rearrange the shop a bit to take our table top (that had been on saw horses) and put it on the ground. The fuselage (which is now on the saw horses) was moved off to the side.
The L-angle that is on the top skin in the rear baggage area had to be removed. Once that was done, we were able to position the cockpit harness mount channel. We marked it the position, cut the L-angle accordingly and called it a night.