With that said, Markiel - Your aggressive stance definitely helps your case staying on a regular. Boot heel/toe overhang is important but even more important is how your bare feet match up to the board. Your bare feet should be equal to or barely overhang the board at your given stance angle. Too much and you'll eat it on a hard carve, too little and you won't have the leverage you need.
Even with your stance I would recommend getting a 161X. On a regular I think you'll be fine with your front foot at a 27 degree angle but the back foot may cause you trouble from time to time. Either way I don't think its the end of the world if you stick with a regular. Good luck!
Yep, barefoot measurement is absolutely the best way to gauge waist width... 24.8 is my new golden rule!!!