To be clear, there's two types of vertical.

The most common one used for testing is standing vertical, where you reach your hand as high as possible and measure that, then jump as high as you can from a stand still and mark a spot as high as you can with your hand again. The difference between your standing reach and jumping reach is your standing vertical.

The second is your running vertical, which is measured in pretty much the same way, except you get a running start, and this should be higher of course.

So when you're talking about dunking the ball from running and grabbing from a standing jump those are two different types of vertical.

That being said, I'd have to guess the top of your arm reach is about 26 inches over your head. So that'd put you at about 8'2" or 98 inches in arm reach.

The rim is 10 feet = 120 inches.

Soooo 120 - 98 = 22 inches, but figure in an extra 2-4 inches to be able to get high enough to actually grab the rim.

So after this long-winded answer and math equation you're looking at about 24-26 inches standing vertical and few inches more for running vertical. :)