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With my spitfire, being IRS, it was a whole lot more grief to get 4 wheel alignment, did it with string. Started setting fronts parallel, rears parallel, strings about a foot off each side. And lots of tweeking until I was happy the strings were parallel, the car was parallel to the strings, and the wheels were all parallel to the string. Took me a couple of hours, the centrelining being the tricky part. I do wonder if I should have measured a centre point at the front and rear of the chassis to make the centrelining part simple.
I had similar grief with my GT6 convertible that I built back in the 80s. I had the advantage of tracking guages, a (borrowed) caster/camber/KPi set and a factory shop manual. Being a MkII GT6 chassis, it had the rotoflex rear end with adjustable tie bars and I started with a blank canvas, having had the chassis stripped and shotblasted and built it up from first principals.
So I set the front up first, matching it side for side and dialling/shimming in an extra degree of negative camber as I went then turned my attention to the rear and this is where the fun started! I found a wheelbase figure and a rear tracking setting (1/16" to 1/8" toe OUT) in the manual, but quickly discovered I could have one or the other correct - but not both! If I set the wheelbases correct and equal, the rear wheels toed IN horribly, about 1/4" and if I set the tracking correctly the wheelbase was around 1/2" too long. Knowing what rear toe in does to a GT6's handling (it's not nice) I settled for getting the tracking correct and the wheelbases equal but wrong. Even this took me the best part of a day to get set to my satisfaction as every adjustment affected the other settings. The hard work paid off in the end though as once i'd finished, it cornered as if on rails!
Steve