what car is this going in, (my memory is bad, not sure what cars everyone is working on these days....) Is there 4 link brackets already on the chassis?
You almost need to mount the body over it to determine where the rear axle should be. Try to determine what ride hite the chassis should be at, and how low you want the body off the ground, min 3" at nose, 2" ok 12" behind front spindle....
once you have the rear axle location figured out, it is a simple matter to measure up to where the front spindles should be. 103" If you want stagger in there, then driver side would be 103.5", passenger put it at 102.5"
Make up a couple of strut jigs with the holes for the spindles at the center of the tire size you want to use. 2x3 square works well, use a 6' piece of 2x3 on the floor, tack weld the spindle jigs to 2x2 angle iron pieces, offset for the stagger, place this all under the frame with the jigs c-clamped to the 2x3 on the floor, move this all around till you get them where they need to be. Caster should be 7-10 degrees back at the top, and camber 0, use one of those digital angle finders,
Make up a 1" spacer to put in the strut between the strut and stopper for ride hite.
You can use whatever method you like for the top mount, I like to make up a plate and weld it to the tube, make up a cardboard template for this, and cut it out of a peice of moly, or you can buy the mount from mcamis, bickele etc, also the a-arm tabs from them...
bend the top brackets to follow the tube somewhat, this also gives it bracing, but I like to add a peice of bracing in there anyways...just a small peice of plate shaped to fit the tube and bracket.
It is now a simple matter to mount the tabs for the a-arms, the rear one should be 2" or so back from the spindle cl of 103" and the front as far forward as practical.
Make up your a-arms, be careful, you do not make them too short , otherwise you will have a lot of rod end thread sticking out, not a good thing, try for max of 3-5 threads for final front end adjustment.
The rack should also be mounted at the same time as the struts, so you have no suprises with bump steer.
you can do all this on the garage floor, use the digital level to level everything up, and once you have everything set, be careful not to bump anything.
If you do it all on the floor, you can see where everything is going to be, take your time, measure lots, and tack everything . Weld only when you are sure it is correct.
good luck,
I have some pics on my computer, (website is now officially shut down) I can email you if you pm me your addy...