Re: 1960's Falcon Rebuild (New Title)
A cinch strap the loops the bottom of the cover, the cover we used a long time ago had a zip/bungee cord run in a pocket around the bottom of the cover. Slip it over, and pull the bungee taut. Enough tension & reduced circumference to keep the cover below the rubrail.
I like the pvc cover I made out of electric conduit (uv stable primarily, but also slightly less expensive then white sch 40 pvc. I used the gray 1" pipe & regular white pvc fittings.
A strong back, w/ T's to attach an angled upright every few feet:
I added a 90deg sweep on either end capped off w/ a T. 1 rests on the top of the OB, the other hooks over the windshield. I put an 8" piece of pool noodle over the T at the end of the 90* sweep.
Added bonus is that it knocks down quick & easy into a couple dozen fittings & a few legs of 1" pvc, all @4ft. Easy to store & carry to & from boat. An empty tent bag, if long enough would be perfect to tote the poles & fittings around in.