See this thread, it may help http://www.rcuniverse.com/forum/What...1140309/tm.htm

As for mixes, the first idea is to mix out unwanted tendancies, eg if the plane trys to roll out of knife edge, mix in some aileron to the rudder to keep it straight.

Other mixes include mixing the ailerons to elevator to make spoilerons to get stable harriers and elevators.