Topsheet materiel for backyard jib

So, i posted in the build-a-jib cult a couple of days ago and now I'm finished construction on my box, i have a few questions about what to put on the top so it slides. I already purchased a couple of pvc pipes incase i can find anything else that would work. I'm holding off installing the pipes becasue i really like the look of the jib without any pipes ont it.

Now, I'm wondering about some kind of clear, rather transluscent topsheet so that you can see either paint or whatever I decid to put in between the top sheet and the rail.

           Option #1 : An epoxy or polyurathane that can be poored onto the rail. about a few inches think, to make a nice sliding surface.
           Option #2 : Cutting board materiel, I have lots of old kitchen cutting boards at my place, and i was wondering if that would work at all as a sliding surface.
           Option #3 : A paint on or brush on lacquer, also wondering if this will slide, might be better and cheaper then option one, because that way i wouldnt be adding more height to the rail, just 4-5 coats.


Suggestions, comments and experience are welcome and also needed, because I'm super stoaked on this project and i want to try it out, I'll try and get some pics up of the rail aswell