Hi, I have a launching trolley rather than wheels. My main reason is my ability to buy a variety of different Sibs over the course of the season, using a trolley is just a lot easier than fitting wheels to them all
I find a trolley easier to pull than wheels, balance is better and the bigger wheels mean pulling it over a field or shingle beach is simpler. I also like the fact that once you drop the boat in there are no transom wheels to swing or remove.
The wheels wont wear out and if you have a problem they cost less than £10 on ebay.
Does a sib fit on a trolley ? Some do, some dont. If you are worried about the small contact points you can always fit bigger pads to spread the load, I dont bother but I do make sure the main support is around the transom area.