ORIGINAL: rcpattern
The easiest way that I've found is put the airplane in a 45 degree climb, roll to inverted and see what it does. If it maintains perfect flight or climbs, then it is tail heavy. You want just a slight drop of the nose from inverted.
Arch Stafford
It seems that this method is the most preferred among top pilots, I would stick with it!
I think the KE turn test is not good, since you are adding more and more weight to the tail. In pattern a "forward" CG is preferred, since it gives more pitch stability, the plane is more locked in. Actually how much forward is quite personal, but the mentioned test is surely a good starting point.
I suggest you to follow one of the trim charts. A really good (and simple) is that one by the great Don Szczur:
http://www.horizonhobby.com/Articles...ArticleID=1194
Also check Don's forum here on RCU, it has plenty of suggestions even on C.G.