Mick Butler wrote regarding Harry Quinn-
He like all other bespoke builders would build what you wanted if you were paying. His and others normally said built to any specification.
I can say that was true, a friend had a frame built by the Harry Quinn shop in 1975. He carefully specified Campag vertical ends, BB drop and chainstay length. He wanted "no daylight" between the tire and the seat tube, Quinn did ask if he was sure about his dimensions. Then built the frame. Tire roundness was not take in to account it seems. no front shifter could be fitted as the clamp would cause the tire to rub, and no tire beyond a 220 gr. Celment seta could be used as they would hit as well. Even those required careful selection to insure tolerable roundness.
The frame was handsome, in mauve with washers brazed onto the inside surfaces of the vertical ends to build up the thickness to approximate the 1020 forged ends.
Beware what you want as you might get it.