I'll apologize in advance for straying off-topic here.
The title "convertible from 2-door" brought back an old memory.
It was a late 70's Chrysler Cordoba (about 5 years old at the time, IIRC) that came into the bodyshop on the hook.
Somebody had chopped the roof off in a "DIY convertible" attempt.
The rear bumper was about 6 ft. off the ground, while the front fenders were paralell to the ground.
The doors wouldn't close (obviously) and were tied "almost shut" with a peice of yellow nylon rope.
One could only imagine the owner's reaction ...