My personal trailer is a vintage TeeNee. Its a combination of swinging roller bunks under the engine, full keel rollers every 4 feet, and two 6 foot long carpeted bunks located midship. IMHO, after owning many trailers, the combo approach is the ideal solution to launching and retrieving, consistent with good hull support. The bunks merely keep the boat stable from side to side. Once the boat is moved back about a foot, only rollers touch the hull.
If you read enough manufacturer's literature for roller trailers (and do some calculating), the really good ones will have enough rollers so that at full trailer capacity each one will hold no more than 125 pounds. I have run a trailer at 150 per roller with good success. The key is proper adjustment so that you can turn any roller by hand (other than keel rollers). If you look at a cheap roller trailer you might find each roller at 200 lbs.
I'm also a fan of bunk slicks. My jetski trailer has full coverage. Even though it only weighs about 900 lbs, it DOES slide off like greased lightnin. After a little use, the surface of the slicks appear to "chalk". Maybe that's part of the reason they slide so good. In any event, I see no damage to the hull, nor any marks.
My tinny had carpeted bunks and it was a PITA to launch. I modified the whole trailer and now its another greased lightnin. Some people swear at rollers on an aluminum boat citing dents, but that's just not true unless they screwed it up. Mine weighs only about 700 pounds, it has no dents, and my trailer is equipped with 36 rollers of various sizes. Do the math!