I recently bought a Masi Special Randonneur, which I believe is the same frame built up as a multi-speed bike. I'm really happy with it so far. The handling is just right -- very smooth, but not sluggish, and it carries a load pretty well.

It's also (IMO) one of the nicest-looking production bikes around.

As for your specific questions:
It comes with 32mm tires and fenders. It's a pretty tight fit -- you couldn't use anything larger unless you remove the fenders.

I believe the rear dropouts are 130mm, and IGH are typically 135mm. But it's steel, so you can always spread the dropouts.

I haven't weighed my bike. It's not racing-bike light, but I wouldn't call it heavy, either. Certainly fine for a commuter, and I doubt the Cross-Check is noticeably lighter.