I use a company out of WI that I really like called PS Seasonings. I use their Jerky kits, sausage seasonings, hi-temp cheeses, casings, bacon cure, etc.
PS Seasoning I use top round for traditional jerky, and I use flank steak for really tender jerky. With flank steak I bake it at a low oven temp layered with paper towels once done to render out more of the fat. You'll want to eat this within a few days or keep it in the refrigerator.