Bucket seat mounting hole locations

I’m almost done replacing the entire floor in my 65 Valiant Vert. It had some Toyota seats in when I got it, which I sold. I have some original 65 low back bucket seats that will be going in. I’m wondering how to locate and drill the holes for the mounting studs. Can anyone give me a reference measurement from some where? Like a distance from the door sill or something. If not, I’ll just make something up.

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