Well, you might first consider "slicking" up your present bunks.
One way is to buy a block of canning wax. Go fishing; let your bunks sit in the sun while you are catching a lot of fish. When you return to your trailer, rub the paraffin wax on the bunks. That may help.
Some guys buy a spray can of "slick stuff" sold by marine dealers instead.
Some, including me on one boat...add PVC strips on top of the carpet. I cut up a 4 x 8 piece of PVC garden lattice (Home Depot) and countersunk stainless steel screws to fasten the strips down.
Some guys buy commericial made strips...I think they are called SlikStrips or something similar. Neither homemade nor commercial strips should be used on riveted tinnys, though.
I've never put rollers on any flat-bottomed boat. That was because all of the flat bottomed boats that I've owned ( 3 of them) were Carolina Skfifs. CS's are fiberglass and the manufacturer was insistent that owners NOT use rollers. They led us to believe that the rollers will, sooner or later, dent the hull's bottom. I don't know if a tinny would be similiarily affected...but I would be very careful as to exactly where the weight would be borne if I chose to use rollers.
Hope this helps, Rich