45-70 government. You have so many choises of loads from low pressure rounds meant for 100+ year old weapons to the new "absolutely knock-em down" loads from [url]www.garrettcartridges.com[/url]. 415 grains at 1730 fps, wow. Because it's a lever action, you don't have to worry about too light of a load not cycling the action or too heavy of a load pounding the bolt into the receiver because you don't have the right recoil spring. If you're going to shoot 450 Marlin, you're probably going to reload because of the cost of the ammo. If you're going to reload anyway, why not just use the standard 45-70? After all, if the 45-70 didn't work so well, it would have died-out when the army dropped it (the same month my father was born) in 1898. Can you tell I want one myself?
The 357 would be nice for you, because you could share ammo. That's a nice old-time, cowboy feature. Also, the rifle would hold more rounds of 357 than 30/30 or 45-70. That might not matter for deer hunting, but for home defense or SHTF, it's useful.