Where in PA are you? I'm in York County and have two Sniders and some assorted parts. First shot them back around 1986, when bell basic was all that was available. In fact, I shot them up at BlueRidge's Memorial day shoot.
Keep in mind that some models do better with 577 bullets, but the early models because of the Enfield progressive rifling, needed larger bullets to fill the rifling at the chamber. I have heard as high as .585 and .590. However an officer model or civilian model may have standard rifling that is uniform from chamber to muzzle and require a different bullet than the standard military model.
I was given a set of Lee dies as a gift, but haven't used them yet.