I can speak from experience as I corrected the alignment defects built in to a Spydersport chassis for Elan some years ago with rudimentary tools. As well described in Tim's posting last year one needs to have the rear wheels tracking true to spec in relation to the chassis proper, otherwise the car may dog track as did my Elan. Due to the elegant simplicity of the Esprit rear suspension, where the powertrain is on flexible mountings you're best advised to lay out a representative center line using the base chassis alone. Therefore I suggest running a string taped under the measured center at front of chassis ( the major box section which locates the wishbones ) back all the way to the crossbeam, checking that the string line measures dead center at the rearmost point where it can be checked against the backbone, then mark the crossbeam yourself. Bear in mind you want to be confident in the sound state of engine and transaxle mountings ahead of this, so that your datum is valid.
By the way, I later had the Elan checked professionally and my work on this, plus tweaking the front caster was found to be very accurate. What I employed as indicator for toe might be amusing - long fluorescent tubes found in the rented garage, offered up to the tire sidewalls yielded an easily seen pointer for the rear toe. A bit of trigonometry and simple measurement can generate quite an accurate outcome.
Cheers
Steve??
