I used wire bead 28's on Concaves when they were current product. I would stick to wire bead tires on them--there were warnings that their bead shape wouldn't hold a folding tire back in the day, to the point where Specialized included printed, illustrated warnings with early folding Turbo tires.
David Feldman
Feldman's Bicycle Repair
Vancouver, WA
360-694-4228/503-998-7249