Thanks for this wonderful cheap solution. I just picked up a pair of these trays at my local HD. I don't have any carpet in the tub just bed-liner, so I was worried about noise and movement, but a quick trip to Target revealed an answer: for ten bucks I picked up a cheap grey yoga matt. It's big enough that I think I will have enough for under the seat, behind the seat, and lining the trays. I'll post a photo if it all works right. It was half the price of the "trim-to-fit" cargo liner that I was thinking about using, and should cushion much better.