I think the optimization of tube OD vs wall thickness was in practice more easily approached from the other direction. Pick any one of the commonly avialable tube OD sizes which were available in 1/8" incriments, and then optimize the diameter to thickness by reducing the tube wall thickness. For high-quality tubing, a fairly wide selection of wall thickness was avialable, custom builders will oftern mix-and-match specific tubes from different tubesets in order to finely tune the weight & stiffness of the frame. Much easier to fit OD of tubes into available lugs and to match established aesthetics by sticking to commonly available OD sizes. THe only bike part that cares about the exact tube ID is the seatpost and that is easy to specify (or to ream-out). I think that vintage road bikes largely arrived at using 1" TT, 1-1/8" ST and DT because the tube diameters were fairly well optimized to available CrMo. Even thinner CrMo tubesets were available then (such as columbus KL) but by all acounts made bikes that were too limber with standard size tubes and too fragile to use at larger OD.
Thickwalled hi-ten tube bikes probably suffered a bit from trying to conform to the standard tube OD of nicer CrMo bikes. The hi-ten steel was not strong enough to use as a thinner wall but they were overly stiff and heavy because they used such thick tubing. Probably would be possible to have built a slighlty more optimized hi-ten bike using smaller diameter tubing throughout.
Also note that as steel strength increased beyond that of plain non-HT CrMo, it became necessary to bump up the tubing OD by +1/8" and later +1/4" OD in order to better optimize the strength-stiffness-weight ballance to the material.


I have run across a few older mid-low end bikes that proclaim that they used butted hi-tensile tubing. Interesting to see that it was at all economically viable to produce butted hi-ten tubes to compete in the same marketplace as strait-gauge CrMo.