Luke could easily pull off a 2" wide collar, but I'd prefer to taper it at the buckle.
I have both of mine in 1.25" collars now that are tapered to 1":
Both of those collars are made out of 12-14 oz. english bridle leather.
Luke can typically pull off wider collars, but since that leather is so thick, I wouldn't put a collar made out of that leather any wider than 1.25" on him.
Thickness of materials can make a HUGE difference in how width looks on a dog.
If you want 1/2" collars, but if you think that they may look too wide still on your dogs, ask if you can have it tapered down to 3/8" at the buckle.