Most of the Super Duty trucks that my area dealers carry are diesel powered. I see more new 350s on the lot, than 250s. Dealers are getting smarter, if you require a diesel, you should be getting the 350.
Funny thing, at the local CGs, you see most TTs, and many FWs, being towed with 150s. I noticed one yesterday, from another state, a 150 ecoboost, towing a 33' FW bunkhouse, with truck full of family, bed full of bikes and gear.
Whatever works, use what ya got! Lol
Anyway, I think a 350 diesel would be better for towing, but in your case, a 250/350 6.2 would work just fine.
Jerry