I used Linas' engine hoist, carefully strapped to the engine mount, to take the weight off the mains.
The tail was propped up and shimmed until the longerons were perfectly level according to the SmartTool.
It's surprising how high you have to lift the sucker before the mains leave the ground. Check out the angle the tire is sitting at in this photo with no weight on the gear. I basically jacked it up so it was just barely "teetering" between the mains.
I was a little busy once I got it jacked up to where I wanted it, so I didn't get any photos of the "critical" stuff that pertains to alignment, but whatever...just follow the instructions Van's gives you. Here's the gist...
Once the plane is jacked up to where you want it, drop plumb lines to chalk a fuselage center line on the floor. Pick a point somewhat arbitrarily on the gear leg fairing and drop a plumb bob from it. Measure the distance from that point to the center line. Go back to the tail and measure the same distance, and clamp a broomstick (or whatever) perfectly plumb/vertical at that point. Run fishing line or string around the fairing, back to and around the broomstick. Get it taut. Now you just rotate the fairing so that the trailing edge bisects the distance between the two string runs. Repeat on the other fairing, and you're done.
I found that after doing this, I picked up about 9 knots. My true airspeed went from 169 KTAS to 178 KTAS. I'm sure it's a more pronounced speed gain for nosedraggers, since you have three of these fairings to reduce drag...but 9 knots is no slouch in the improvement department. As I've mentioned before, my goal is 180 knots true (at some configuration, I don't care what). It looks like once I add intersection fairings and wheel pants I'll easily be able to hit it.
Also, I found no turning/yaw tendency after installing the leg fairings. I must have nailed the alignment. Too bad the little "tabs" where the fairings get clamped at the top broke after a few hours... This was to be expected, though. You really need the upper intersection fairings in place to more solidly hold the leg fairings in alignment without over-stressing the clamp tabs.