The toe-in spec. I have is 18' +/- 8' or 2.2mm +/- 1.0mm. (' = minutes, or 1/60 degree, but you won't be able to measure that, so we'll stick with the toe-in distance. Toe-in distance is defined as the difference between the centre points on the front of the tires and the back of the tires. The 185/65-15 tires are 24.5" in diameter and the wheelbase is 109". So using the proportion of 109/24.5, lines projected along the sidewalls of the front tires should be 2.2mm x 109/24.5 millimetres farther apart at the rear axle, which is almost 10mm, or 5mm per side. So sighting along the sidewall of the front tire should put you about 5mm, just under 1/4" outside the rear tire.

I seriously doubt if slight variations outside the toe spec would be noticeable. Even greatly increased toe-in will only show up as tire wear, but toe-out will feel darty in a straight line. I find steering wheel misalignment more annoying than anything else, so always get alignment done professionally, just like dental work.
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1992 745 approaching 500k km