FPMSL - neasrly crying here, that really tickled me .
Big Yinn, you are, shall we say, a whole lot of man? Your caffeine intake is very high, but it maybe doesn't affect you so much for that reason. If you're at the stage where you get withdrawal headaches, then I would say you are just on the wrong side of too much. Clearly you're concerned about it, otherwise you wouldn't be asking.
If your body is inflicting pain on you then it's trying to tell you something.
Try cutting down over a few weeks, and then see if you can do a morning without any coffee. If you can manage without a coffee (i.e. no headache), then I'd say you're at a safer level.