Marty,
I believe the brake cable braze-ons are positioned with the Tektro (or other?) sidepull brakes in mind. I think that is what Rivendell will tell you, at least that is what they told me. A centerpull brake will definitely work on the front but the rear is where the creativity comes in as the cable stop is canted over to one side, I think to allow better cable routing for a sidepull brake. That said, people have figured out modifications to make centerpulls work, though usually with a fair amount of work.
Search the list for "cheviot brakes" and you will find more info and some pictures. The shop that built my Cheviot used a variation of what I believe Rene did (with Paul centerpulls) and it worked beautifully though I will say no more... The bike is perfect though, at least in its context, which is pretty much *my* context these days! If you use FB, search for "Queen CIty Cycles" and scroll down to the grey Cheviot build.
Bob Lovejoy
now in Galesburg, IL...