I like it!
I notice some differences between your rifle and my own 3" Jeffery such as the top tang on yours is wide behind the trough and abruptly tapers back to the top tang, where the Jeffs have a pretty much straight taper and the horn tip has a bit of a shnabel shape.
Peruse EBay etc. for a Lyman. I think you can modify one with a longer base to bring the screw holes where you need them. I would maybe reconsider fitting one though, especially if you plan on shooting anything close to full loads. Sticking with the NfB loading would be the way to go as mentioned above and it will still be potent but an enjoyable rifle.