darock is right. I find the extra tension very helpful. The tension also increases slightly as you move away from center and the spring stretches.
I also fly with thumb on top of stick with no problem. I teach both methods to my students and let them find the method that works best for them. It varies. We even have one guy in our club who flies with slight down trim all of the time. He wants to hold up elev all of the time for some unknown reason. [sm=bananahead.gif] His flying suffers from this but we can't talk him out of it. Usually lands on nose wheel first and bounces to a stop