Sub-frame connectors

This doesn't necessarily guarantee level or square. I would measure and double check. Floors aren't all perfect, nor are jack stands. You may already have done this, but I would hate to see anybody make a simple mistake.
yep. stick a level on the ground dead senter between the stands in the center of the car and see if its level. then set it under the exact center of every jack stand and check that too. Make sure everything is as level as can be. Its better to be anal and 100% sure. This is coming from my stand point. mr. worrisome himself. lol