Oh yeah, I forgot about drilling a hole under the tank. I do that too.

Another durability tip I'll offer, and I consider this a must do with any film covered plane, is after tightening the covering with an iron I wick thin CA along all the seams. Yes, I know the adhesive for good covering is strong and completely fuel proof. However, oil creeps its way into the tiniest of microscopic openings and over time will lift those seams. I'm sure thermal cycling, humidity changes and vibration play a role there too. But if you will wet all of the seams with CA and let it cure on its own (no kicker), it will seal up all those microscopic fail points and will definitely make your covering job last longer. There are few things worse than having the covering come off of the horizontal stab in flight then pulling it off to find oil saturated wood on a model you truly love to fly.