Frame Connectors?

weld type is what I like, and I like to have the car on a level ground [if it's a non flogged car] to start then when I've welded I can get to, I put the car up on stands square at all 4 corners to finish the rest of the weld.

If it's a car that when you jack it up at the rear frame behind the door and you can watch the door/jam gap change drastically [flogged car] I instead start with it on stands as far in as possible to try and bend it back and keep it there.jmo