450 Marlin loads

Hi - I am just about to start reloading for my 450 Marlin (a Guide Gun with a 18.5" barrel).

There seems to be some quite variable reloading data out there - including comments around the extent to which it is or is not like a 45/70 (noting my understanding it is slightly smaller in case capacity but can handle slightly higher pressures a lot better).

Does anyone have some good loads (ideally with 325gr FTX projectiles) - appreciating of course I will need to work up to them.

Although I can comfortably manage a dozen or more shots in a session, I don't really fancy trying multiple powders with multiple loads (for obvious reasons)...

One day I would also like to give some cast bullets ago - any known issues re these and micro-groove barrels. There appear to be all sorts of 'internet experts' with different views on this as well.

Thanks,
Ben

I think action strength/style is going to be the limiting factor
Its like a long 450 Bushmaster IIRC and guys are getting SILLY speeds out of them