Just buy an SLR camera
Like you, I learned to practice guessing distances and got pretty good at it. However, I suspect that what you find on say a measuring tape or laser rangefinder readout is not going to translate exactly to the distance markings on your lenses, which will result in approximating where to set the distances anyway. The reference to SLRs was made only half in jest, because if (for instance) you want to get just the eyes in focus on a subject w/ a fast lens wide open, you really need an SLR for that. Same w/ close distance focusing made wide open. What you see in the viewfinder will be exactly what you will get on your neg.
There's also the idea of using more modern cameras. I have a Nikon AF n8008s that is used with older Leica R and other non Nikon manual focus lenses. It has a focus confirmation light in the bottom corner of the viewfinder. When the green dot is on you have exact focus. Not exactly sure how that system works, but it is extremely accurate.