I don't have that particular model but I've got a OL crewneck in linen from SS12, and they seem to use the same cut / fit for most of they're crewneck knits.
I got it in Large, which is my usual size. It fits a bit boxy and kinda short. It's about 25" in length taken from back of the collar while the chest is 22", to give you an idea of proportions. It looks great though if paired with slim trousers (not chinos) rather than jeans.
I don't think I could have sized up to get better length, since that would only further increase the chest and boxiness.
I take a large in GBV and in this seasons SNS stark and most of their non-super-fitted knits.