How would you bend this frame back?

I'd say those hydro lines are magnetized and the roof rails bent towards them and .....caused that car to float in the background. Lol
In all seriousness, I'd take it to a convertible top shop and see what they say. Bets on they've fixed one before and you don't risk ruining it. If the cost is too high for them to fix, they'll probably tell you how'd they do it so you can DIY.

HA! And I thought the car was nicely waxed. Come to find out it glows in the dark.

I didn't have any luck finding a shop that would adjust my windows to seal up with the convertible top. I'm still about 1/4" short on one side. Maybe there is a top shop around here that is hip to bending the frame. It's interesting how many shops don't want to touch this old stuff. That little itch in the back of my mind is telling me this could be a personal growth experience if I don't get ham handed with it.