I have a fairly nice 25 year old fillet-brazed steel Santana Sovereign.
I'm thinking about putting fenders on it, but not sure what kind to get. I do have experience with fenders on single bikes, my current bike is a Surly Pacer frame, and I have very nicely installed Planet Bike fenders with mudflaps. They fit perfectly. I have the "Sheldon Fender Nuts" on this setup,
which allows the fenders to be bolted on from the back of the brake nut. However, the setup on my tandem is totally different. First I will describe the front fork. The clearance between the tire (28mm, it's as narrow as I'm willing to go) and the top of the fork is just barely enough for a fender. There is enough space, but the clearance on the back is twice as much. The fork is not drilled through because it has cantiliver brakes. However there is a threaded hole on the back of the fork. This hole appears to be the right size for bolding on fenders with normal sized tabs. However, since I'm not using Sheldon Fender Nuts, the tab on the front fender will probably end up hitting the headset parts, so the fender tab will probably need to be bent back to avoid hitting the headset parts. The Sheldon Fender Nut allows the tab to be further back, clearing the headset easily (see photo attachment). Next the rear fender. The tire clearance is very adequate. the mounting hole on the back of the "bridge" is tiny however. It appears to take a much smaller diameter screw than the front. My worry is that the hole in the rear fender tab will be much larger, and the small screw through the larger diameter tab will be very sloppy. There is also a threaded hole at the bottom bridge near the rear bottom bracket. Of course there are eyelets in the fork and rear dropouts for mounting the fender stays, and these appear to be standard size for accepting screw sizes that would normally come with Planet Bike fenders. One other minor issue is the wheels are 27 inch, whereas modern fenders are 700c, but it's so close that I don't think it'll be a problem.
So my question is, what would be good fenders to get? Are there any fenders that would be better suited to the very small mounting holes on the bridges on the back fender? Also with about 1.2cm of clearance between front tire and fork, will this be enough space?