i wear a single ply f6 in size 44 and this is my comp. fit. i would like to get ahold of a 2-ply f6 and use my single for openers. what size f6 (2-ply) would suit me best? titan recommends going two sizes up, and according to them, ill want a 48 in their 2-ply. my training partner argues that i need a 46 (he wears sz 44 katana, 44 f6, and 46 f6 in 2-ply). i would like to hear from folks who had expierence with single/two ply shirts.