I read about the need for double rollers with the Getaway and made something else that works pretty well.
On each single roller I placed a 16" piece of pressure treated 2 X 6. It runs lengthwise under the skeg. Under the 2 X 6, I screwed 2 pieces of 1 X 2. They are perpendicular to the length of 2 X 6 and are placed just in front of, and just behind the roller. They keep the 2 X 6 centered on the roller, and from rolling forward or backward on the roller. On top of the 2 X 6, I screwed 2 more pieces of 1 X 2. They are each 16" long and run along each side of the 2 X 6. The skeg of the boat goes between these and they keep the 2 X 6 from sliding off the roller sideways. With the boat sitting on these "pads", the pad can't move forward, backward or sideways. I made four of these and carpeted them.
I roll the boat on the trailer. Then I lift up each corner of the boat and set these "pads" on the rollers. Now, instead of each corner of my boat resting on 1 or 2 square inches, which could cause dents in my hulls. I have each corner resting on 16 square inches. I trailer it with them on and let the boat sit with them on. I only take them off to roll the boat on and off the trailer. They lift on and lift off, no tools needed. They are simple, cheap and functional. You can make all 4 of them in 20 minutes at a total cost of less than $5. Your hulls will like them.