For grins you should try some RL17. That could be a good powder in that cartridge. It might even match or exceed the 7RUM. In my 300 WSM the charge was 1 grain more than H4350. You could call Dakota and I believe they'll have load data for H4350.
The 7 Dakota is a great cartridge, would love to have one someday. Let us know how it does for you.