Here is the best example of trying to figure out the height of ape hanger you want to get.
Have someone help you out.
Sit on your bike, stand it up, straighten the front wheel, grab a stick and hold it up to where you're comfortable.
Measure from the bottom of existing bar to the stick.
This example is a set of the 12" Outlawz measureing at 12".
This will get you as close as possible without actually mounting bars.