I read in a column written by Mo Pinnel in BTM some years back, that the formula for revs to speed ratio should be about 1 to 1, meaning if you throw the ball with 17 revolutions you should be about 17 miles per hour (off the hand), at least to carry like the pros do.
That's not to say that if you throw the ball with 13 revs you should throw it 13 miles per hour, because there may not be enough oil on the lanes for that slow of ball speed, or too much oil for 24 x 24 or what ever the case may be. I'm not saying that if those are your specs you will not be competative on those conditions, just you will favor either oily lanes or dry depending on your specs.
What Mo was saying in the article was to check your specs and try to get as close to the same number of revs as mph and adjust your equipment from there. For instance if someone is tossing the ball with 13 revs at 18 mph they might want to either learn to put more revs on the ball or take some speed off the ball. If you are at Robert Smith level the 24 revs, but with only 20 mph you might want to either back off the revs a bit or up the speed, but from what Mo was saying the most versitile speed to rev ratio was between 16x16 to 20x20.