Weld subframe connectors loaded or unloaded?

I'm planning to do mine with the frame on jackstands, but only because I found that the doors and windows worked better with it that way. I lifted it up on a set of QuickJack scissor jacks to do all 4 tires the other day and noted how much better everything worked. I also have cracks on my rockers at the back edge of the door, so pretty sure my car is sagging already and could use a boost before getting stiffened up again.