I modified the seat floors (as many others have done) to make it possible to remove the seat stop easily and remove the front seats by sliding them aft.
This involves drilling holes for nutplates in the seat floors and replacing the hardware with bolts that are inserted through the top of the seat stops. This allows a socket on an extension to be used between the sidewall and seat to quickly remove the stop.
I secured the rails into place and match drilled the seat floors on the drill press. The bit fit loosely and didn’t affect the hole in the rails so I didn’t need to use a drill guide bushing. I put some Boelube on the bit before drilling.
I then match drilled the rivet holes for the nutplates. The edge distance from the lightening hole ended up being 2x which was sufficient. I had considered putting these nutplates on an angle but I noticed that the top of the center section bulkhead might potentially interfere with the shop head when I test fitted it.
After countersinking and deburring the holes, I riveted the nutplates into place.