I run downtube shifters on my road bike, and my downtube is oval rather than round. So the shifter boss covers arent shallow enough to fit snug agains the frame. I've found there are 2 types of these covers - flat and radiused. The flat kind is too flat, and the radiused kind is too round, I need something shallower. Anyone have a source for something like that? Below is an example of a radiused cover:

https://www.ebay.com/p/Shimano-7800-....c100005.m1851

Shimano made only those two types of boss, flat and concave.

I just use a Dremel tool with a sanding drum to shave off a little of the radius on the concave mounts. Works fine, takes about 30 seconds per boss.

Thanks for posting. Yeah I had wondered if there were only the two types of covers, and had been thinking a 'custom' version might be the only way to do it. I guess by the time non-round shaped downtubes came out most bikes were using brifters.

A file. There are some convex metal files that you could use, set on a table, run the backing plate back and forth on them.

Rough side out, I assume?

This issue is a Goldilocks one, for sure.