A short Class C "under-loads" the E450 chassis, so anything and everything negative about handling will be less with the Ford E450 (ton-and-a-half) chassis under any small Class C that could be built, weight-wise, using the E350 (ton) chassis.
If you get a small 24-25 foot Class C make sure it's on the E450 chassis regardless of it not being necessary, weight-wise. I'd definitely run from any longer Class C on the E350 chassis ... I've even seen a Class C that looked to be 28 or 29 feet on the E350 chassis!
By the way, the E450 chassis has a wider track in the back than the E350 chassis does ... so right from the start the E450 will provide more lateral stability than the E350. The E450 also has other advantages over the E350 for motorhome use.