I'm putting some Stronglight 200lx cranks on a Vitus 787 frame. Both are new to me, so there's no precedent to compare to. I know a need a threaded 68mm square taperered bottom bracket, but I just can't figure out the spindle length I need.

Googling around seems to suggest it's a case of just trying a bottom bracket and seeing how the chain line is. Is that really the case? And if so, what's the best guess I can go with?

Thanks
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