I have thought about different ideas along those lines. I like the tune-ability idea, but recently I have been going a different direction, so it would actually counteract the idea of prolonged exposure... unless I'm missing something.
If you cut out the top and make it one hole... you'd have an R-Hop or ER-Hop...
Not sure what you're referring to with shimming the hop up... I didn't reference anything... I think, but maybe I missed something...
Here is an analogy of how I am looking at this problem... in principle, not really application. Think about bowling:
Varying weight balls
I won't elaborate on the "proper" technique for bowling, but typically there is s spin, be it back or lateral spin that people will use to get the ball to where they want it to go.
With this in mind, a traditional/modern hop up would be like cutting your throw short, releasing at the hip, and flicking your wrist to put a dramatic spin in the ball as it goes down the lane. For some people this works. However, if you watch professionals their movement is fluid and almost slow, they have a long release and a lazy rotation on the ball as it goes down the lane. This is almost the effect that I am looking for in the BB with this hop up.
To paraphrase what I said in my last post: long, consistent, gradual exposure to the hop up is the goal.
But enough about my stuff, I'd really like to see what other people are doing....