Did I buy too big of a prong collar?

I bought a prong collar for my ~45 dog because she pulls/bolts after squirrels and such to the point where shes choking without use of a choke collar, and all around I'd like her to be more responsive to me while being walked. I bought the "medium" size because shes not a "small" dog, but upon reading how to properly use a prong collar I've taken off the appropriate amount of prongs. It came with 10 or 12, but to properly fit her, I've gotten it down to five. Too little?