I might make two 10 foot rails for my backyard to use in winter and then summer, and I am wondering if I should use the same design as I used for my 14 foot rail up north. My rail up north it is probably 6-7 inches wide with a pvc pipe on either side of the rail. Here is a pic. My question is does have only 2 pvc pipes instead of covering the whole wood surface area make a difference while sliding? Does more pvc pipes give you better friction/grip or anything? thanks