Make sure you add a drop of Prime or what ever you use to the bag as soon as you open it. The link below explains why.
I use the first method described in the link with all types of inverts: shrimp, Dwarf Crayfish and Thai Micro Crabs. I've had minimal loss of RCS and 100% success with crayfish and crabs. I say "minimal" because I get 20-40 at a time and it's hard to tell when adding to an existing population in a heavily-planted tank.
However, if you had success with drip acclimation, I'd do as lilnaugrim suggests.
Not to defend PetSmart, but poor Ghost shrimp are feeder shrimp and raised in a way that doesn't lead to being healthy. I've had a lot better luck with RCS and Blue Velvets than I ever had with Ghosties.