I played with 4451/210 Partition. Can't say it was better than H4350, but initial indications show it's worth looking into more. Very temp insensitive! Too slow for a 180/185 unfortunately.
Just to add, IMR 4166 would be the only one that might be fast enough. I'd email Hodgdon and ask if they have loads. They did provide me loads for 4451 and it included, among others, the 210 Partition. It only went down to 200gn bullets.