Seat rail mount with Selle Royal saddle

I just replaced my Fizik saddle with a Selle Royal Respiro saddle. The seat rail mount I was using with the Fizik doesn't work with the S-R. I had it mounted on the vertical rails at the back of the saddle and need to put my Varia in the same place, but the rails are a different width/angle. Does anyone have any suggestions/recommendations for a new rail mount for my Varia?