Weld subframe connectors loaded or unloaded?
Doesn't matter loaded or not, JMO.
I tack the connector to the torsion x-member, start jacking it up against the car, check door alignment, open/close door for best operation, find the sweet spot and finish weld them in.
As someone else mentioned the build tolerances on these cars are horrible. Wheel tubs with 1/2" more clearance on one side than the other and folks are concerned about likely less than 1/8" with connectors.
Got a car on a rotisserie, put a laser pointer on it near the rear spring mount on frame pointing level with rocker towards front. Piece of metal/cardboard up front and note pointer location. Flip the car over and see how much it changes. The one we did wasn't worth fretting about. Totally insignificant change.