The Llewllyn parts will work with other brakes, that's easy. Paul brakes need something to fit into the adjuster. If you look on Darrel Darrell McCulloch's flickr, you can find a number of examples. They work best for randonneur racks.

I would suggest anyone that wants to build a rack look on flickr or instagram for examples. The only problem with flickr is that people love to post pictures of public bike storage racks, and they dominate searches for "bike rack". You have to add search terms.