I can get about 15 min out of a 10oz tank, for my OS 46AX with a little to spare in case I need to go around a couple of times, the engine is set just a little rich so full tune you should get at least 12 min with some extra room for landing with a 8oz tank.

I should add I set my timer for 12 min after I warm the engine in the pits for the first flights all I can go is about 15 min max any way without getting a little burnt out