I've used a 23.5' E-350 phoenix cruiser to launch my sailboat (23').
It's straight forward but a big novelty for the idiots that like to watch in the hope that you get into trouble.
As the sailboat had a small keel, I would be in water all the way to the front of the rv before it was deep enough for the boat to drift off the trailer. There's no problem unless (as some one said earlier) you stall. Then you're in trouble. I never had that problem myself.
With a longer class C, the problem I can foresee is if there's a lip at the top of the slip. with the long overhang, the front of the trailer might be so high in the air that the back hits the slipway.
It really depends on what's on your trailer and is something else to eyeball at the slip before entertaining the idiots.
Putting a tow bar/ball on the front would be a viable fix for a slip with a significant lip though.