Like the Boss basically said, assembly is the key. Almost any helmet can be assembled to have a larger opening and possibly more room inside. Its all about the faceplate placement. That doesn't mean it has to be a low brow either. I first built an AP before I knew anything. I didn't know that I could adjust the build to fit me. It was like medieval torture to put it on and take it off!... and that was with trimming the opening larger! I'm not even going to mention what it was like inside....
I compared a VT I had to my ATA and AP. The VT mold size is definitely smaller than the ATA and appeared smaller than the AP!
First, follow Nate's list - that is based off the actual mold sizes. The bigger / taller you are the more you want to stay at the top of the list (minus the FX of course and the ANH V2 is one piece, so you can't do much with it). Second, before building do some mock ups with tape to hold the parts in place and try it on. Worked for me!