Jeff: I'm glad that "King of the Mill" found a flaw in the span of your grip. From what you described, your span is way too long and needs to be adjusted. Shame on your current driller for doing such a poor job.
Having said all this, don't be surprised if the new relaxed grip with zero on the thumb pitches feels strange at release. And by strange, I mean possibly feeling like you can't get out of the ball. Anytime you introduce a change as radical as what you are going to try, it can be tough to adjust, even if it's more "correct".
In my case, I experimented with taking just 1/8 inch off my span and going from 7/16 to 3/16 reverse on the thumb. Well after one year of this, I'm going back to the longer span with more reverse. Despite all the hype about relaxed spans and zero (or even forward) thumb pitches, it just wasn't for me. It worked OK and felt great gripping the ball, but we all have different levels of hand flexibility, and I could not get 100% comfortable at release.
I gave you my experience not to discourage you, but to indicate that the change you're about to try might not be the final answer. Go with the King's recommendation, but don't be afraid to try variations if after a period of time it doesn't feel right. Keep an open mind, experiment, and you'll find the right solution. Remember, with respect to grips, there isn't a universally correct answer for all.
--------------------
"Advertisers -- you too can have access to this prime demographic"