Several years ago, there was a vendor online selling something similar to what I just made here for much more than this cost me.
This is for the two vertical edges. It now matches the trim on my plastic tub. I'm quite pleased with the aesthetics of this.
This is a lighter weight aluminum piece of diamond plate that I bought at a local Home Depot for $26 and had them cut for me to size.
They also had the steel which I considered once before but decided against and simply was using a plastic corrugated piece with plastic 3M hooks.
The HD guy made two cuts from my measurements; one horizontally and one vertically, using tin snips so this would be easy enough to do vs the steel diamond plate that requires power tools. I affixed it with
3M 15lb rated Outdoor Velcro. For now, I simply added the two Velcro strips while I wait for the rest of the trim.
I had a leftover trim piece from the tub cutting mod I did for my sewer hose. I doubt it would budge but I decided to remove it for storage (in case of theft) and transport. I like the way it looks and it's an easy and inexpensive mod.