Mrbelair, I like how you narrowed the C4 batwing. I had a customer wanting a narrowed batwing because he's narrowing the suspension and we raised it higher in the frame than stock, and he went with one from a Viper. We raised the humps as well, so I don't even think he needed to do that. Unfortunately it's going to take a lot of welding and machining to make the Viper batwing fit the C4 center section casting. I think it would have been much easier to narrow the C4 batwing but I couldn't talk him into it. Someone told him they didn't think he should weld on it so he stuck with that.
I'm not sure I understand why you went with the notches in the frame. With the halfshafts level I have about 3 3/4" between the halfshaft and the bottom of the hump. Since it's an IRS, you actually get quite a bit more than 3 3/4" drop at the wheel. I did a frame once with Shockwaves and we were able to get it almost to the ground with a stock frame hump. I think the stroke of the shock was more of a limiter than the frame itself.
I assume you're going to raise the dogbone attach locations too? The top one should be level or slightly high in the front.