Clinchers? You poor people. But as you did not say...
I have 28mm tubulars on the tandem and love them. If you are much under 300# 28mm tub is too much tire for paved non pot hole roads.
A true 25mm (as in measures 25mm) tubular is good for most pavement even chip sealed.
I'd go tubular 25-27. I don't get clinchers for anything but convenience and glass and Goat Heads...
Clincher add about 3mm and 50% the mass and you get about the same cush. The feel you don't.