Specific 944 advice aside (as I don't really know all that much about them!) get it done properly.
These cars are meant to be driven, everyone talks about the balance and the handling of the 944, why bother with a crap geometry set up?!
Use a placed that has the kit, and knows how to use it. Stick your postcode into
http://alignmycar.com/ (Hunter wheel alignment website) and see who is local.
Don't confuse setting tracking with setting geometry.
I'm sure axle stands, string and rulers will get you a decent result (in fact when I replaced all bushes and more on my Elise last year, I used axle stands and string to make it drivable to get it to the geometry place, and the initial reading was actually pretty close to straight - not that you want straight mind..!)
My local non-specialist side street garage, who I've used for all of my cars (944 and Elise included) for my whole driving life has Hunter Hawkeye Elite gear, it's among the best on the market, and I can tell you first hand how impressive it is. It uses clever wheel mountings and cameras to locate the 4 wheels, and allows the mechanic to adjust whilst the reading is being taken, so no guess work.
Chris