Nice looking pair of bikes!

You can feel free to also ask in the Clydesdale section, but I weigh 350 pounds and I ride any 27" tire.

A couple of my favorites are the same that others here like. The Panaracer Pasela TG or the Continental Ultra Sport both ride well.

Just be sure to keep the tires well inflated to avoid pinch flats. If your rims don't have hooked beads (and I don't think they do if they are the stock rims) then stick to under 80 PSI or so on the inflation, regardless of what the tire sidewalls say.

If you are staying at 80 PSI and having trouble with pinch flats, I would suggest switching to hooked rims to allow for higher pressure.