I've built some pretty cool stuff out of PVC pipe using the trial and error method, no plans at all. I built a workbench plan stand that has a flat side, a V-side, and a side with one flat and one V. Build two identical ends and connect them with the appropriate length PVC in the middle. It hold the airplane beautifully in any configuration for installing radio gear, engines, covering, etc. The pipe insulation is a nice cushion.

I built a car rack that holds wings and airplanes without the hangar rash I use to get from just throwing them in the trunk.

As far as I'm concerned, PVC is too cheap and too easily taken apart and rebuilt to do anything about preparing plans. After all it doesn't have to fly! It's an erector set for big boys. Just start cutting and fitting and cutting and fitting. Glue it together only when you're satisfied.

A search for plane stands will turn up some photos of other others' creations.

Good luck