Have the same issue coming up for my 6CM. The article in the 2018 Hodgdon manual has data that indicates that the best choice depends on the powder, and/or your use. Superformance seems like a great powder for hunting loads, and heavy target bullets and LRs seemed to work best there, but the examples are very limited. Both types gave very good results in certain case. I figure on getting some of both types eventually.
