Originally Posted by Salamandrine

I guess I was thinking of the entry level Ultra Sport. Comes in 700x32, and it's cheap. Next up is the Ultra Sport. Max size 700x28. I think the Grand Sport is in between. Also comes in 32c. There's also Gatorskins. Continental tire line is confusing, it's true. FWIW I haven't used these personally with concave rims, which I have not owned in decades.

If you want to spend a bit more, it'd be hard to go wrong with Paselas. It's clear from the other posters' actual experience that they play nice with concave rims.