I'm 5'6" and 155, so shorter, but rounder than you. I own the Hadron Anorak in a small and am very happy with the fit. I just gotta be a little careful pulling it on and off, but otherwise, it fits really well. I still have some room for a thick baselayer/fleece, but it fits snugly enough to be very efficient.
The wrist cuffs are quite tight though, so be aware. I keep mine stored hanging with tennis balls or tubes of whatever stretching out the wrist elastic, so that they will loosen up over time.
However, the tightness isn't a real problem or anything, good for sealing in the warmth and whatnot.
Got mine off geartrade.com for a great price, so maybe you can snag one there too.
For layering over the ex-light, get a medium. Large will be far too big for your dimensions. There's another thread on the forums, and people larger than you have been happier with mediums.