My mistake. I thought you were talking about the other shower floor.
I went out and took some pictures of my shower area now. The aluminum angle along the two side is where FRP with go up those walls. When it is done the FRP will come down over the metal angle.
The whole shower/bathroom/closet access area is 36 inches wide by about 52 to 54 inches long (the front curves out). I put 3 drains in the floor to account for a sometimes unavoidable leveling problem. I usually have the CT a little off level intentionally for the shower and the head of the bed. That also makes it easy to predict to what corner my shower water will go. I use a bucket under the appropriate drain to catch the water. I shower everyday, but since I boondock exclusively, I only use a half gallon or so of water.
Here is a picture of the two drains towards the back. The unfinished or open wall shows my under the seat storage. For now it is behind a curtain. Soon it will be behind a wall.
This is the front shower drain. Complete with my broom and dust pan.
The bench is usually down over a portapotty, trash, and sprayer.
I run the curtain across in front of the bench. With the bench down the shower area is about 36 X 40. And looks something like this:
The FRP holds up very well. We used the shower area daily for 4 months straight last year. It doesn't show any wear, even from our muddy boots. We like it, and it works well for us. We hopefully will be finishing it this spring. We have FRP walls, new curtain, closet doors, cabinets on the front end at the top, and a mirror/medicine cabinet in the plans.
Hope this answers some of your questions.