ehh.... i assume you mean in terms of diameter ? hmm I'm not too sure about vic firth sticks but based on the specs of the 8DN given from the vic firth website, it has longer reach and similar to the 7As.
Hmm, you may wanna try out mike portnoy sig. His sticks are somewhere in between 7As and 5As but with longer reach.
Maybe its just me, but I feel that pro mark sticks are usually heavier. You may also wanna put that into consideration.