How to locate cab corner on '66?

[Railroadman]

I'm sure this has been discussed before, but when I did a search most of the threads which looked promising were hundreds of posts long! So I'll start a new one.

My '66 seems to be quite typical of many rusted out cab bottoms. I have a whole bunch of panels from LMC and am starting the process of healing the sick (or maybe raising the dead!)

I'm at the right rear and there is nothing left for vertical orientation of the replacement cab corner. Front to rear I have pretty well, as the lower front pillar repair piece has been tacked on and the outer floor and rear pillar piece bolt together. But the corner piece seems to lack an obvious reference or location mark that I can see. How do I figure how far up or down to install it?

Thanks!

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