Don't understand why some use "Dry Weight" when trying to pick a truck to tow a TT or 5er with. It's really not much help or "real world"...Do yourself a favor and use TT's GVW when purchasing a truck to tow with...no one tows a TT "dry" or "empty", and believe some would REALLY be surprised if they weighed their unit, when loaded..I know I was...Weight can add up quickly..
If your present truck tows it fine, go with another 1/2 ton...if that is all you need and you're not planning on "eventually" getting a larger heavier TT or 5er...then, as someone suggested, I'd also recommend you look at a 3/4 ton to "already have one" in case you decide to go heavier later down the road.