Wanted to post a pic, but da wife is off to work with the van

So, never having had to install shocks before, but doesn't look like rocket science, my questions are:
- Am I right in assuming that I can just tighten down the hex nut on the forward surface of the shock mount to pull the bushings in tight? (looks like about a 19mm socket) or will this be pulling other things out of alignment?
- If this is so, can this operation be done with the suspension loaded - i.e. with the vehicle just sitting on the flat normally, or do I need to support the frame up and get the rear wheels off the ground to do this? (I am hoist-challenged). The fact that I can wiggle the upper end of the shocks by hand leads me to believe that they are not supporting much, if any weight (should be the springs' job). I don't want to torque them down and bend the shafts of the shocks out of true if they are under load.
Any pearls of wisdom to impart? Thanks,
Tony.