Sway is mostly in the WDH and it's setup and also the TV. Difference between 28' and 30' is almost nil. I would not buy a smaller trailer to start as when you go to sell it, you will lose a lot of $$ - better to put those $$ into a nicer truck, TT and/or accessories. Will also depend on where you will be driving and the CG you'll be going to. Use a good WDH with integral sway control.
We started off with a 20' TT (and F150). Only lasted a year as it quickly become too small. Towing and backing up was easy and could drive through a crowded parking lot no problem. Moved up to a 29' TT along with an F250 SD with a long wheelbase. We're on the west coast and the new truck has been great with all the mountain, twisty, steep and bumpy roads and the F150 wouldn't have worked for us. The only real challenge I find with the longer truck and trailer is in overgrown CGs and it's imperative to have a spotter when backing up. The higher wt. of TT + TV is definitely noticeable but I got used to it quickly. Need to be careful when looking for a gas station - don't pull into one unless you are certain you can get out okay.
