I would think that taking one shim from the outer leg of the nearside swinging arm and adding it to the outer leg of the offside swinging arm will effectly alter both from pointing to the nearside (kerb). But the thickness / number of the shims that you need to remove or add will be trial and error, surely?
I would have thought that the ideal would be to get both rear wheels parallel to each other by the adding / removal of the outer shims on each swinging arm using the 'factory' number of shims as a starting point; once they are parallel, then you have starting point to adjust them equally to give the 0 - 1/16" toe in (as stated by the workshop manual). Only then should the toe in of the front wheels (1/16"-1/8") be set relative to the rears.
I'll stand corrected, but I was taught to get the rear track / toe in correct before setting the front. If the car isn't travelling straight at the back, then the front has to compensate for any inaccuracies. If you set the front first, then alter shims at the rear, the path of the rear will then dictate the position of the front wheels either slightly to the left or right to compensate and then throw the spokes of the steering wheel out, especially if the rack and steering wheel have both been previously centralised. As the path of the rear wheels are in a fixed direction, the toe in should be set correctly and equally before any adjustments to the front. If the rack is centralised (as discussed previously) and the steering wheel then centralised on the column and the clamped, the front tracking / toe in can be adjusted equally. Theoretically, everything should be then centralised and the car should drive straight without any 'crabbing' caused from the rear track being incorrect.
You can set and check the rear toe for 'parallel' using the bar method. I have some cranked aluminium adjustable bars that sit on the floor and you adjust the width against the inner edge of the rim. When they are parallel, the bar should fit snugly between the front edge of both wheel rims, and then the rear edge both wheel rims. There is a scale to indicate the difference between the two edges of the rims. The toe can then be adjusted by removing shims of equal thickness to the 'outer' legs using the scale to measure the toe in.
I appreciate your wheel alignment chap is going to be more knowledgeable than I am, but I fail to see how you can set the rear toe correctly without at least some form of measurement (however basic!), before moving to the front.
I hope this makes some sort of sense..

Register Member no. 1596
1967 Mk1 2000 in Gunmetal Grey
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