Typically I buy my sub-primals at SAMS though come next March we too will finally have a Costco in our community. What I like to do is go to SAMS like on a Monday or Tuesday when they have replenished their meat cases from the weekend. Most times there will be a couple dozen or so cryovac packages to sort through. I like to look at both ends to get some idea of the internal marbling in each piece. I’ll even start out selecting a good one and then keep selecting and after getting 4 or 5 in my cart I’ll pick one out of the bunch and buy it. Good luck!