Question about axle angle shims

[Serious Johnson]

I scored some fresh-ish 4402/4408 springs cheap, but the fronts are set-up for a spring-over, and include some rather steep shims (about 3/4" over 4"). I'll obviously need to re-shim for proper pinion angle when I re-jigger for front spring-under and the persumed 3-4" lift that these springs provide. Is it as simple as splitting TC/diff u-joint angle at static height, or is there more to it than that?

Thanks

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