Dan, on your seat bending observation, '73-74 seats have the back frame welded to the seat base frame. These welds are often cracked on one side or the other. The '71-'72 seats are made in 2 separate parts using four large allen bolts to hold the backs to the bases. You should check which seats you have and if they're cracked (unsafe). The early seat construction not only eliminates seat-frame cracking, it allow one to change the recline angle of the backs a little by loosening the bolts behind a seat, adjusting the angle and re-snugging the knobs.
Since I added 2" OD knobs to the seat-back bolts in 1988, I can adjust our '72 for seat-rake in seconds while driving (on straight roads). Makes long road trips a bit more comfortable in 99%-stock seats, with no travel delay or cost.. Further, by cutting the bottom of the slots off early seat back straps, the backs can be easily folded onto their bases for working around the rear firewall, without removing bolts, only loosening them.