LS, the 500 S&W uses large rifle primers. You can use standard primers, at least I do. There are some early brass out there that use large PISTOL primers, the brass that's supposed to be used with large rifle primers have a R somewhere on the headstamp.
The best powder for that cannon is Hodgdon "lil" gun. It'll give you more velocity than H-110/296, with less pressure.
As far as tricks, I don't know of any, except that huge case is really hard to resize after firing full house loads. And yes, I do have carbide dies, I usually put some case lube on them,(small amount or less that if it were being sized in steel dies). Oh, make sure you get a firm crimp on the bullets. Bullet jump is worse in this revolver than any other.
This is the 700 grain "grand canyon" HP special order mold from over at cast boolits.com
The big smith, that belongs to my SIL.
When fired with those beasts, it's almost impossible to hang onto it! This started with a 2 hand hold-----.