1. Your story of bending the canti post to align the brakes is giving me heart palpitations. THe brake posts are a structural part of your frame and fork. Bending them is not desirable.

2. Other models of old high-profile canti brakes came with a bevelled washer that went under the post of the pad, and rotating this washer before tightening the pad down would change the angle of the pad.

3(a). My experience is that old 'high profile' cantilevers are pretty much crap compared to newer low-profile cantilevers, and complete crap compared to V brakes or mini-v brakes (direct pull brakes).
3(b) I recently overcame my chronic cheapness and replaced the MAFAC cantis on the rear of my bike with a cheap (like $12) set of Tektro mini-vs. Night and day difference. You would experience a similar improvement with a set of modern inexpensive Shimano low-profile cantis, which are much easier to set up as well, compared to your old Di-Yeung brakes from the bottom of the ugly pile. The new brakes also come with new pads, and are only slightly more expensive than a set of aftermarket pads alone.

https://www.bikedoctor.ca/product/sh...e-374611-1.htm