deerslayer - your gyro has a trim pot on the receiver. The CX2 manual spells it out pretty well. Make small adjustments - the manual will tell you which way to trim it to correct tail drift.
I have found that a 1/8 turn is a lot. Always test your corrections with your transmitter trim centered. You do not need to replace the front cowling between tests - this will speed things up a bit but remember that the cowling does provide protection in a crash so leave it off only if you are comfortable doing so. Good luck.
Snobelt