I'm 6'2" and currently 215 pounds. I have a Large in everything Rapha. I would definitely not get an XL. You want a tight, but not too tight fit. Check their sizing chart and also know that they are easy to work with on exchanges. Just try it on once you get it and figure out if the fit will work or not.

Let me know how you like the Core jersey. I was considering splurging sometime around my birthday on maybe that and a set of core bibs.