G'day Carl. In reply to your question as to how much fuel should be left -

I generally put one size larger tank in models than is called for. If I can't then I just live with it. Most planes will give about 15 to 20 minutes if built as designed AND not flown at full power all the time. I generally find that my planes have at least half a tank after flying for 8 to 10 minutes. I don't use a timer most of the time.

Dead stick landings are not the disaster many people think. As you recent "landing" shows, you can land just about anywhere. The trick is to make it a landing and not crash. As someone said here somewhere - "A bad landing is always better than a good crash."

I would try to leave about 20% of the tank. That will give you a couple of missed approaches at least and then if the engine does stop, you should not be too far from the strip and a dead stick is not going to be too much problem. Mind you, if it is really windy, then a bit more reserve is probably a good idea.

As for the cluck and not much fuel - the clunk follows the fuel no matter what the plane does so you have to be pretty violent to get the clunk to leave the fuel even if there is not much left. The trick here is to not make the clunk tube too long. The clunk should sit about 1cm (3/8 inch) clear of the back of the tank (a bit more in really large tanks) so that it cannot ever touch the back of the tank and restrict the flow. I don't use the light tube provided in some ARF kits. It is too light and splits easily. I generally use Dubro clear light blue tube as it is easy to get and good quality.

Cheers

Mike in Oz