"I balance mine pretty tail heavy"
I just went out to the shop and measured it. 2 1/2 inches back and I am still adding 1/4 oz. every couple of flights. It gets better all the time. What happened is the muffler got loose during a flight and fell off and all of a sudden I had a great stunt plane. Of course the engine really roared and speeded up but the important thing is it changed from a very stable, smooth trainer into being capable of square loops, vertical 8's, etc. I had already moved the pushrod to the hole closest to the hinge line in an effort to get more manuveability and all of a sudden I had it. I will continue to add tail weight until it gets "twitchy". My guess is that I will go to at least 3" back. My handle spacing is about 4 inches, I have not measured that. Oh yes, I put the muffler back on. If the wind is reasonable, it handles overhead 8's really well with good line tension. I am the problem as I tend to lose balance and get dizzy trying to look straight up (maybe 72 years has taken more of a toll than I want to admit, when I last flew competitively I was only 18). With a 9-4 Master prop it really hauls and my reactions are not up to the speed. Now I use an APC 10-3, run it just on the rich side of flat out, about 10,000 to 10,400 at launch. It is usually too windy in this part of Oklahoma to fly a wet cycle.
Jim