Hard to tell without knowing your PAP.
For (dare I say it?) most right handers, that's probably drilled for close-to-maximum flare (3 3/8in. pin to PAP distance) with a hook/set backend to control over-reaction.
Anyone feel free to dispute that, as I am no super expert.
Why don't you plug the thumb and if you don't like it's reaction, re-plug the entire ball then?