This is pretty much what I did. I used XV (now defunct) connectors which welded to the floor all the way. I leveled it and hung the doors. Then tacked it real good, then raised the rotisserie off thr jacks and turned it so it was easier to weld.
Now the car is completely assembled and has been driven with no noticeable issues.
Boy what I would have given to get it done that way, learning to weld, and laying under the car with molten rain falling on you . . . THAT's a learning experience !
And it would probably lend to nicer resulting welds too . . .