I would say TTS but you could maybe go up 1 if you want an oversized fit (just keep in mind sleeve length--don't want them too long). I'm a 48 and have the bottom one in a sz II and the fit is spot on for me. If you're looking for a II feel free to PM me. Letting mine go to put money toward other purchases.
Edit: actually might know someone with a III available if you're looking for that size, though not sure he's committed to selling. Edited by pickpackpockpuck - 8/14/14 at 5:24pm