Master set is <b>everything</b>: parallels, sp's, ssp's, inserts, etc. only exception that can be made are plates and 1/1's, though some would say by definition, you include those, even if it is unrealistic
some sets are great for master set building, particularly in the early 2000's. the more current, the more parallel's, the harder it is
some sets are great for master set building, particularly in the early 2000's. the more current, the more parallel's, the harder it is