Winter is a pretty difficult time for color. I still don't know what you think ginormous is? And yes, that is the way we measure, just the largest single rosette. Not the entire clump.
As Chris said, many of these may be green in the winter. There are some that may stay darker in the winter. Many of the hueffelii are dark colored year round.
heuffelii 'Aprache' is a larger one.
