Not a fan of rear living rooms, dinette-only seating, and snug bathrooms I would chose the 30 if you plan to someday spend lots of time traveling in it. It's three feet longer, but the maneuverability in the campground will have more to do with truck wheelbase than trailer length.
You've got a great hitch in mind for comfortable towing in all conditions. Start towing with light loads in both the truck and Airstream until you get a feel for the combo and what it can do, your level of satisfaction. We have had three half-tons towing Airstreams and like them.
Doug and Cheryl
2012 FC RB, Michelin 16, ProPride 1400
2016 Ram 1500 Laramie Crew Cab 4X4 Ecodiesel 3.92 axles
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