Yes the numbers are exact science, but the fact is that coverstock makes up 70-90% of ball reaction depending on who you ask.  This doesn't render the core irrelevant, because they do design cores and covers to work together, the core is just in much more of a support role.  Take certain lines of bowling balls.  Often you have the same core or a core very similar, but differences in coverstock or coverstock prep.  Take the IQ line from Storm.  The IQ Tour, IQ Pearl, and Tour Fusion all have the exact same core with the exact same numbers.  Can you think of 3 more different reactions?  Those 3 balls are significantly different motions from each other, all achieved with different coverstocks.  You take the same cover and put it on a wide variety of cores, and you'll get a much more similar motion between all the balls. 

The balls I selected happened to have the right numbers because that's how they were designed.  Because of that, I can go off reaction and design or intent rather than the tech stuff.  You'll get closer to what you expect or want by just looking at ball reaction and the design intent than you will by ignoring it and just looking at the numbers.  Or basically it sounds like you're just making it more complicated than it needs to be. 

Gizmo,

Looking at your decision process and looking at the bowling balls you selected, the RG and Differential seem to coincide with descriptions you were looking for in each ball. Yes, the coverstock, is just as important too. I am just stating, I don't think its a bad thing to base some of the decision making on the RG and Diff values.

Just recall. My initial question. Are these numbers and exact science? And the first reply I got back is "YES".

Quote

Read what the ball is designed for.  It a combination of cover and core.  The cover playing the bigger role.  Watch videos to see how it roles.

Disagree! Yes its a combination, but they both play a role equally on how the ball roles. Both are important, not one being more important than the other. When you state that the coverstock is the bigger role, makes it seem that any core will work. You know that is incorrect.

So 70-90% equals 100%? 

Obviously if the coverstock is 70-90% of a ball's reaction, the core still matters.  You're trying to act like I said it doesn't matter at all.  Obviously if you use two identical weight cores with the difference between the 15 and 12 lb values below, you're going to get a difference in reaction.  It just won't be NEAR as different as if you put the Tribal coverstock on this core instead. 

I should have done this in the first place, but here, enjoy: http://www.bowl.com/uploadedFiles/Equip_and_Specs/Equip_and_Specs_Home/08ballmotionstudy.pdf

Scroll down to page 13 for a graph showing and ranking the importance or influence of different things on reaction.  The top 5 factors on the list are related to coverstock. 

So for the Covert Revolt, the 12 lb ball will get same reaction as the 16 lb ball.

BALL: Covert Revolt
LANE CONDITION: Medium Heavy Oil
INNER CORE: Vanquish
COVERSTOCK: Turmoil HFS
FINISH: 3000 Grit Sanded

WEIGHTS - RG RATING - RG DIFFERENTIAL - MB DIFFERENTIAL

16 - 2.46 - .057 - None
15 - 2.47 - .056 - None
14 - 2.50 - .056 - None
13 - 2.56 - .044 - None
12 - 2.63 - .030 - None

FLARE POTENTIAL: 5"+

That's cool haha, I'm enjoying the debate.  Yeah it's REALLY hard to know who to trust because everybody is an expert.  There's a guy that lives around here that's on staff with Brunswick, and everytime he gets asked about a ball or how it's drilled, he says he just throws them and to come talk to us.  So not everybody that throws them good knows anything about them, but sometimes people who aren't the greatest bowlers have a lot of knowledge and are good coaches. 

It sounds like your daughter is at least out of the beginning stage.  For younger kids, I'll always point them towards the lower end stuff.  For older kids, even if they're still beginners, I'll recommend something more mid range.  Just with the extra strength and coordination that age brings, older kids have the potential to become better faster.  Older kids also tend to develop and learn at the same time, but there's only a limited amount that younger kids will actually learn, most of the time you have to try to develop coordination first with them.  Without seeing her bowl, it's tough, but I'd recommend something like a Hyroad, Venom Toxin, Eruption Pro, Melee, etc, things of that nature.  If numbers are your thing, stay around 2.50 on the rg, and around .030 on the differential.  Even though these will change after drilling, they still give you an idea what the ball is designed to do.  Should give her something relatively smooth and controllable. 

Thanks for your input Gizmo. I am not trying to start an argument. I am trying to understand. I live in area where there is not a lot of knowledge in this sport. I get conflicting information all the time.

My point in all of this is not finding the right ball for me, its making the right decision in getting a ball for my daughter. She has totally different bowling style than me. (I know what works for me is not going to work for her). This quest I am on is to get one or two balls that will work for her for next year when she competes.

I have seen many people buy the wrong ball for their kids based on a friend's (with a high average) advice. I have a little bit of knowledge in this sport, and we all know that is worst kind of knowledge to have because I can easily make the wrong decision.

The local pro shop is not reccommending anything specific. Bascially stating any ball will do. I think there is some balls better suited for her than others (Maybe I am wrong, it wouldn't be the first time or the last).

Again thanks. You responded, and gave time to answer, it was appreciated.

JLS??? Must be hungover from the Masters to be on here talking about bowling. I know I am going the other direction. GOLF ON!!!