Subframe Connectors....buy or make?

I welded mine sitting flat on the rotisserie. I was concerned but luckily had no issues with suspension alignment and door alignment. Launches straight .But I do see your point.
My Ragtop never saw a rotisserie but Upper door gaps were closing up slightly after 200K Miles so I nervously hung the back suspension down then welded. Gaps came out the bomb. I was Leary and wouldn't recommend it. I was a bit lucky.
I would think doing the subframes sitting on the suspension 1st before putting on a rotisserie would be a better scenario .