8th - I have sleeved a glider before and it does add a ton of strength at the cost of weight. I did both a full body sleeve and a nose only sleeve. The full body sleeve could have been used as a billy club
For the PX, I would suggest using a single layer of carbon weave. It is 1000x easier to cut, takes less epoxy and it is easier to put on the plane and overall much thinner.
Here is a link to an ad where a member was selling a nice piece of carbon weave...
You may have to PM him to see if he still has some in stock.