I agree that the Heavy Blues 2 is not going to be a good choice for the neck.
That being said, I haven't tried it in this position (i'm using it in the bridge).
But given how bright an brittle my bridge sound was before and now how I usually have the oposite problem on the neck I know it wouldn't work for the sounds I'm looking for.
I can see how it would give you a lot of range (very dark bridge to bright bridge), but I would think a lot of that wouldn't be useable.
IMHO

Yep....I'm now realizing that the combo recommended by DiMarzio isn't a very good one after all. What's up with that? It's easily conceivable that their automated pickup selector tool doesn't take into account the combination of all the pickups at once but rather looks at each pickup in isolation (which is a flawed system then if that is in fact the case) to achieve the desired tone but the live tech person I was emailing with surely should see the downside of such a combo....right??

They may know something I don’t and may have some logical reason, but I just don't think it's a practical configuration.
They do have a good return policy, so if it doesn’t work for you they will give you something different.