Sorry to bring this insignificant matter but... how does the Paul Racer work on the bike? Better than the U shimano? I don´t care about looks.
Why does this question also sound like an insult?
Ha.
I do have a lot to say about how it works, tho. I just hadn't got around to that part yet!
Regarding the sleeve issue: I chose, probably somewhat controversially, to resolve this by removing material from the stud, rather than try to have a custom sleeve made. (My brief discussions with a machinist were promising, however he felt the likelihood of them lasting too long was slim, given how thin the material would need to be in order to fit over the studs and still work as a pivot inside the brake).
I have no reason to think this bike will ever not be in my possession (it means too much to me in the way it was built and who contributed to that) so I felt comfortable making the decision to alter it in this way. If I ever wanted, I could always have the studs removed and replaced with new ones to run a roller cam, or regular U-brake, I or could possibly have a custom shim made to fatten the existing ones.
Other than the sleeve, there were no other issues at all in terms of clearance, or pad positioning against and away from the rim. Everything worked and there was now ample clearance, with no annoying rubbing, for my tire of choice, even when hammering the pedals on a climb. It's tight back there, sure, but in a pleasing,
track bike kind of way.
The brake functions really well, and stops firmly. It is, however, a little spongier than I would like. I plan to pay around a little with straddle length and further refine the spring tension to see if this can be improved, but it may well be that it's simply because of the flex in the ti chainstay. In which case, my other planned improvements are to try some high-end compressionless housing, as well as purchase or fabricate some kind of booster for it. Not a bad thing to have as a guard against damage back there, either.
I think both things will help drastically and I'll make sure to report back once I know for sure!