Keeper of Spider Hill
You are on the right track. We use self drilling screws for all of our static and animated PVC prop kits and they work great. The trick is not to over tighten them. You want to make sure you slow your drill down as the screws tighten so you don't strip the PVC. This will also allow you to remove them if you need to break your prop down for storage. You can find self drilling screws at Home Depot and Lowes.