Danno-
Okay, now I know what you mean!- The P 18 hulls do "fatten up" on the inside- One thing you can do is reverse the rollers- That is, put the vertical rollers on the outside of the hulls (which on the P 18 are much "flatter" than the inside). Position them so that with the boat all the way against one roller at least some of the horizontal roller is still under the opposite hull (otherwise that hull can scrape on the beam or roller end rod). You can also bend the upright roller by putting large steel tube over roller and pushing (if galvanized though this may crack galvanizing). Only downside I know of this is the rollers tend to stick out and can "catch" clothes, legs, etc. so may want to pad end (if not already). This should allow you to get boat further up on trailer. For the "black streaks" you can either replace your rollers w/ the (expensive) clear (or slightly yellow) rollers, wrap in (good) white (or whatever) tape (will tend to come off and need to be replaced periodically), make/get some cloth "covers" that fit over the rollers, or cut some white PVC tubing to slip over your black rollers. The white PVC can be bonded to the rollers directly or you can drill holes and tie bottom so won't bounce off.
What number and sail pattern is your boat? Can't remember my sail number right off hand (7XX?) but mine is a "reverse" Tequila sunrise (green at the top, light blue on bottom)- I guess you'd call it a "Tequila sunset"?? One thing I like about the Prindles is the sail patterns are different (from the more common ones you see)-
Kirt