Mix tips? You said it was some local "engineer" who did this right? How much control do you even have here in the outcome. Honestly, there is A LOT wrong with the mix. Just about everything really. Im not sure what to critique because if it was me, I would change everything. The guitars are an issue but I cant tell if its because they are in drop Z flat or because of the mixing. The drums are not terrible but they need some humanization. I don't know man, I could go on and on but I think the best idea for you and your band would be to drop the 8 strings. You don't need to rely on super, over the top, drop tunings in order to be heavy. Obviously its not exactly doing wonders for your tone either. That's all opinion anyway I suppose. If you like it then more power to you. I wish I could be more helpful here concerning the mix but I don't even know where to begin.
