[lukevanoort]

I know this isn't too helpful, but I'm going to recommend having an adjustable setup. If you're making a PVC roofish thing set it up with a pair of collars in the middle of each pipe with a pipe between them that you can swap out for different lengths. My father and I use this method on out ghetto canoe outriggers in case we catch the "big one" (wishful thinking, I know) and it works perfectly, allowing us to adjust lengths and angles for the amount of stabilization we need, and drag we're willing to put up with.