Mark, I hope you know that I like your design, it's creative and it looks great I was just concern about the feel of it. Now that you said it sits in the right place then the other issue would be that it's top heavy. OK, what kind of kit did you use, and how much of the weight of the dice row was finally drilled out yielding the weight of the upper part.
Here is an idea; what if you use a smaller dice to drill out most of the material yielding to a less weight to kind of balance the top heaviness. Or if you can cast a blank resembling the dice, but less heavier, so your design concept is not impacted and you can keep the weight at a more comfortable feel?
BTW, wouldn't Tru-stone add more weigh to overall desgin and therefore the pen?
somehow, I think you need to keep the look meanwhile reducing the weight.
the other point that comes to mind is that don't dices come in diffferent materails for different hands and games?