I had ones like Astra's on a similar sized boat, and they were excellent.
The balloon ones you mention, I assume they are like the wheels on a Dyson Ball or a Ballbarrow, aren't to my mind really practical.
Years ago I had some on a very early 10' Humber Rib, and they rolled easily over almost anything, BUT I like to put my wheels down while the boat's still afloat, and these wheels were so buoyant that it was well nigh impossible.
There are also tiny wheels that fit permanently on the transom and flip up when you're afloat. Never tried them, but saw someone here at Blakeney using them and they looked to be very hard work. Just too tiny.