Hi,
When I switched from a Hobie 16 to my Prindle 18 (same trailer), I thought it looked like a lot of weight on the single front roller. I thought about picking up some fiberglass hull cradles, but instead went with a double roller system. This spreads the weight out quite a bit. I have some photos of it at http://www.thebeachcats.com . Just go there and do a search for "double rollers".
Good luck,
Jack Hoying
Prindle 18
Fort Loramie, Ohio