Dick thats a great report. I'm happy that your results are good so far.\
I had some yaw instability with my Spark and it was very uncomfortable. I added the stab fences and it really helped but on my plane I found that the more I moved the CG aft the better it got. I sometimes think a nose heavy plane lacks that locked in feel.
Everyone I know with the Contra has added the do dads to the rudder. Good luck with learning it. Mike