On the topic of long sleeve polos/knit shirts, I bought one of these at Haneda airport without trying on:
It's size S and just a little too tight for my post-holiday gut. Liberate it from my clutches for $50 shipped, if you care to...
Tried the F on yesterday, and while the double monk accommodates my absurdly high instep, I struggled to even get my foot into oxfords. Went up a half size, and was swimming in space, especially across my toes. Go figure.