I think you’ll do fine – just tried my pair on with some anti-glare glasses and although the pads do press against the sides it’s not noticeably uncomfortable. My head shape is almost perfect for Audeze headphones, though, so take my opinion with a grain of salt.
For me, none. I have a pretty big head and my LCD-3s fit snugly with little to no clamping force.
Always attempt to try on a new pair of headphones if possible, though; for example, despite much praise regarding their comfort I personally have found the 6x0 line to be the most clampy headphones I have ever tried, enough so to give me a headache for the rest of the day after a 5-minute session.
thank you garfield’s ejaculate