The problem with grafts is that the scion grows at a different, slower rate, smaller than the understock (usually less), so that the difference only becomes more and more apparent. Add to that the very substantial difference in bark as in JWP and JBP and that aggravates the situation. Unfortunately, that means that after you have put in your time and effort, years down the time line, you get what you get. You have little or no control over what that is, but the odds are not in your favor. Are you feeling lucky? Shoot the moon. Me, I don't have time to waste on trying to beat the odds. These are never the cheap stock, either.
How about all of you out there in bonsailand show me photos of a "good" graft on a tree with some age! Finished trees. Hmmmmmm? SHOW ME! Prove me wrong as many times as you can. There will be lucky trees out there, but with thousands and thousands of people on this post the numbers will tell the tale.