Replying to Rail question

So my friend and I just got hooked up with some free 3" diameter PVC (schedule 40 actually, but same idea) pipes, and we were talking about how we should set it up and he thinks that we should use the pipes in a double barrel, but I think using 3" diameter pipes in a double barrel would almost make it too easy (it's almost as wide as a box), so we should just use 1 of the PVC pipes. that would help us get comfortable on more challenging rails and help improve our balance. what do you guys think? Thanks!