What I am about to say might sound like basphemy...but if you check the date line, I think the foillowing brakes will fall within the CR rules.'
In the late 70s and early 80s I built a lot of time-trial machines with what were known in the trade as "fag-paper clearances" ie the thickness of a RIZLA brown roll-up paper..or at least theoretically so.
So dogmatic were some customers that they specified the actual tubulars to which the frames should be built, those made Dugast and Assos, sometimes SOYO being the finest at around 17mm. Woe betide the happless time-trialist if they fitted WOLBER 19mm and did not strap and bond the tubular tight to the rim arounbd the valve-hole ! No I am not pulling your legs!
The brakes used by most riders were those radical Dia-Compe 400 with the elliptical pad adjustment. If you could afford them, and for the psychological edge they gave you, you would specify the all-black MODOLO Kronos..or that manufacturer's cheaper model. For the rider who thought "outside the loop" the very light and mall MAFAC Jacky braze-on was the most in one-upmanship, lightness and effectiveness. Weinmann also had the Delta centre-pull, a sort of forerunner of the Campagnolo of the same name, that had a very short reach.
Norris Lockley
Settle UK