Can anyone advise/help please with following? Is there a rule to follow as to the type of roller and where they should be on the trailer? my boat is 14ft speedboat, cathedral hull,almost flat at stern with very steep rise at bow, my trailer has (from stern) V-roller, then combination roller, ie; same V-roller with 1 4inch wheel either side, then another same v-roller, they look as though they are original to Snipe make of trailer, is this the correct combination/layout? thanks for now JBD.