I have a sturdy piece of angle iron fastened across my door openings while the car is apart. If you look at the "Eastwood" catalogue you can see their fancy door brace with turnbuckles to be used on convertibles.
Before the car is off the Hoist and on the rotiserie I weld a angle Iron across the top of the door and a angle braket up to the top of the weindsheild, I bolt ot on and use the holes for the visor at top.it is very important that the wiondsheild frame is exactly in the right place or top and doors will not line up and it moves out of line very easy!
GORD.Canadian 4 amphs
You need to connect top of doors and an x inside too. Another place for some angle iron is in back along the horizontal bumper floor. When trays and qtrs are rusted or cut this area likes to drop. You can extend radiator support out towards back to find proper lines if drooping has already begun. Later Dave the Wave