Sheesh dude. Are you a glutton for punishment or what? You narrowly missed the bullet on the last project and now you're looking to tackle another one!

If I was going to do it tho, I'd think 'shower stall'. I bet those sheets like they use in a campground shower woukd block moisture like crazy. I wouldn't use those stupid plastic rivets to hold it up tho. I'd attach it with stainless screws with rubber washers under the heads. You could caulk the edges with siliccone sealant.