Most studio , military and photo-league darkrooms I worked in used the average 50mm lens for 35mm and 75mm for 6x6, and so have I continued to do so, though ultimately, I'd prefer the El Nikor 63mm for 35mm.
I have a 25mm lens for 16mm negatives, and I've used 75mm at times for 35mm printmaking, from which I learned the valuable lesson, that some photographers of smaller medium format films would take their intense desire to use the 75mm enlarger you're currently printing on.
This happened to me one day, after a league photographer I knew to be a good printmaker and had a conniption because I was using the 75 mm lenses enlarge I pretty much always did, for my prints.
The several other 75mm equiped enlarger were already engaged, and he just wouldn't understand I was there, on that enlarger for a long printing session, it still makes me chuckle, the public funk he went into.
I also remember another printer, using a 75mm enlarger, getting disgusted by his moanings and giving up her printing station just because she could not enjoy her printing because of his behavior.
For 4"x5" I have other, longer lenses, but I've yet to get a 5"x7" capable lens for my 5"x7" enlarger and future negatives from a pinhole camera.
It sounds, in part, that 80mm ~ 6x6cm pairings is more of a European standard, but am I wrong?