I use the RadTech cloth on the keyboard of my 16", but am disappointed it doesn't also cover the trackpad. It does protect the screen from the keys though.
So far so good, but just today in fact I decided to cut the sheet that came with my laptop from Apple to make a cover for the trackpad. That sheet is so thin I cut two rectangles so it's double thick. Do note that the two sides of that sheet are not the same - one side is much smoother, that side goes against the screen.
Real pain in the ass to have a RadTech and two sheets of that paper to deal with, but whatever - my MBP will never leave the house so I can deal with the hassle.
Edit: got some double sided tape and taped the two sheets together which makes things easier. Also the strips of tape sort of bolster the thickness within the borders of the trackpad, providing a little extra leveling of the sheets where they transition from the palm rest to covering the trackpad borders.
The things we do