Recommended string gauge for Drop C#?

Currently my Schecter Omen 6 has Ernie Ball Power Slinky's 11 14 18p 28 38 48 and I am considering changing to Beefy Slinky's 11-54. My guitar scale is 25.5 and I get quite a bit of fret buzz on the 9th fret with the Power Slinky's. Beefy Slinky's good for a 25.5 scale guitar in Drop C#?