The Super Ground vs Super Race in the same tire and size will be interesting. Schwalbe themselves still claim the Super Race as the faster tire. My only concern would be year to year variation in the tires given the prior reports of some inconsistency with Schwalbe tires.
Separately, there has been lots of discussion regarding the 2.1 TB as a fast option for gravel. The 2.1 size squeezes into a number of popular gravel bike frames. However, for bikes that have proper clearance for a 2.25 (ie rated for it), would there be any reason to not run the 2.25 TB in that case? This is assuming it would be used for a course that is primarily gravel and not primarily road.