A tiny pumper would be the cat's meow. Today was goooood. The 13x6 is THE hot ticket with this plane. After 2/3 of a gallon I decided to lean to peak and back down a touch then filled the tank (4oz !) and went out to put the plane through the paces. This was the first really hard flying and it performed very well. Full throttle most of the time through big outside loops, rolling circs and attempted snaps.... The engine ran more than 10 - 12 mins and when I landed I noticed a high idle. The tank just had vapors, man that sintered clunk is outstanding with smallest Tygon diameter. Macs pipe is perfect no leaks and hard to get the engine over 295F . Idle could be as low as 1750 ( rough) smooth at 2k , smooth again at 2450 and this is where I left it. I can't recommend too much that a high quality mid size digital servo be used to make sure that the position always returns to the same place ( Spek 5030 for me). It makes the idle so much more stable and easy to trim.