You can try using a .409" bullet for a start, that is what I have for both my .450/400 3 1/4" rifles, one a double and one a Jeffery Farqharson

If that will chamber you should not need dies as the case should chamber without FL resizing
You would have to shoot it to see how accurate it is

Decap, load and use a vice (carefully!) to seat the bullets Q.E.D.!

I bought several F/L dies from CH4D including a .450/400" 3 1/4" which, when I take the decapping rod out, will size/seat/crimp. This would be ok for a single shot as a tight crimp unnecessary, but the wrong way round for your shorter cases

Good luck whatever you choose

TH44