I bought it in Mke and while I've had a few issues with it overall it's worked ok. The guy at the show did say just spray it on and let it work, but when he demo'd it he kept rubbing it in. When I let it sit on my tunnel I got streaks and it did not work uniformly. The next time I used it I sprayed a lot on, and rubbed it in the entire time, then wiped it off after about 3-5 minutes. Seemed to work ok then. I've never used a hose and he may have told that to you, but I don't remember that part.
I do like their polish (small bottle of green fluid) as it seems to work well without much effort. Here are a few shots of the pipe, belt cover and can. I've never done them before and it took very little to clean them up. I haven't cleaned up the tunnel from the ride a week and a half ago so no shot of that yet.
One thing I do remember him saying is that you have to polish it after you clean it. Not sure if you did that in the photo of your trailer fender. I haven't worked on my trailer so I can't comment on how it works there.