MEC is the brand name leader in the field and a single stage press is the way to go to learn the tricks of the trade.
I hunted for years with an accomplished and hyper-proficient gunner. He made all his own shotshells and he was what you could call particular about his work. When I sat down to learn the art I was told the rules are there to keep you and the shotgun in one piece.
What little I recall about shotshell loading is this:
1. There is a recipe that defines the hull, the steel, the bushings, the powder & charge, the buffer and the crimp.
2. There is very little divergence allowed from the recipe. No roll your own.
3. You have to follow the rules exactly.
None of this should surprise you, it is quite similar to loading centerfire
My Friend killed ducks at 50 yards with 2 3/4 lead and he used Pillsbury white flour as his buffer.
Best of luck
