Ooooo I like that QuickTrick tool - you know I googled my little heart out for something around that price and came up zero. Looks pretty neat.
Regarding Squaring up - essentially you make sure each end where the string connects to the bars is the same width - i.e. you pick a width that is great than the car.
Then to square it you need to ensure the strings are the same distance either side from the front and rear hubs.
Its a little bit of initial fiddling because the front and rear tracks are different (thats why I made the slide adjusters). But once you get it square I then just put insulation tape marks on the front and rear square alignment bars.
I have had it on and off the car multiple times and all I do is double check the square and hub distances and it comes up the same each time.
For Camber I have a very crude method - I have a square bar attached to a spirit level and I put it against the wheel rim edges and measure how far out the top edge is from the rim for a vertical spirit level etc. I then use a little spreadsheet with a TAN formula in it and I enter the value and it gives me the angle. Its probably not uber accurate but does the job.
Caster - I havent done that. Too hard for my small brain to figure out :-)
My car tracks pretty well at the front and the feel is right with the power steering and all so I am assuming caster is ok.
Its been too cold and wet here to test my new adjustments though. So I might have stuffed it up.
Attached is what I ended up with.
The camber is a bit much for street but I left it for Nationals in Oct. The rear camber is adjusted all the way in so thats the best I can do.
cheers gregg