I'd suggest getting some of the foam sheeting available at a Home Depot type store. Look by the sheetrock and wood. Some debate pink vs blue, but any is better than none.
As to raising and lowering the motor, I like to do this. The motor is the most expensive part of my boat so I'll try to protect it as much as possible. I saw my dad leave his motor down pulling the boat out of the water. It scrapped the ramp a bit - then when the trailer tire went up a tire catcher on the ramp, it lifted the motor off the ground, and when it came back down, the motor slammed into the concrete. Broke off the little piece on the bottom that looks like a keel. It's kind of funny now, but not at the time. He also broke an axle on the same ramp a few years later.