I am going to go against the grain here and tell you to get the GM! The PM is really too small to fit your daily essentials --- well, at least it was for me, lol --- so even though the GM is huge, it really doesn't look that big because of the slouch factor.
If you can, try on both the PM and GM size and see which one looks better for you. In my case, the GM worked out best and I am two inches shorter than you! Good luck!