I always thought that the snuffing bag should be made out of water resistant material so the spinnaker will not get wet. My snuffer bag has open end but when the spinnaker is snuffed there is no way for the water to go through. So what material should snuffing bag be made of?

I made my snuffing bag out of ripstop coated nylon and supported with sunbrella material by the hoop see picture attached.

What should be the diameter of the snuffing bag? My hoop is about 12 inches in diameter and the whole bag is about the same. When I installed everything on my boat I saw bag dragging in the water. Should I taper it on the back?