I dont believe its formal at all, but I guess that depends on what color/fabric you get. Im about 165 with a 38.5 inch chest and a Medium fits me well. I would say it runs a little smaller than most brands.
I take back my original quote. They will ship to the US. I tried tohave them ship some Waxed Flesh Vibergs earlier this year and they wouldnt. The wingtips are supposedly an E Width though. Might be a good opportunity for some. Im still going to email them to get the details.