Brake Pad bedding / Rotor deposits

[DJbrand1]

I have a 944 Turbo S with the Big Blacks up front. I use the car for DE's. During street duty I have some cheap Metal Masters, before an upcoming DE I switch them out with some Pagid Blacks about 5 days or so beforehand and use them lightly to try and scrub off the Metal Masters coating on the rotors. Getting to the track I'll find some back roads and drag the pads lightly to try to get some heat in them then perform around 6 medium to hard stops from 60/70 to 20 mph. After, I return to the track using the brakes as little as possible to cool them down. With this procedure I am still getting some pretty bad deposits on the rotors and get a lot of vibration. Anything I am doing wrong here? I drove around a week after the track with the Pagids still in to try and scrape the rotors clean but so far no success. Is the last resort to get the rotors cut and try again? Thanks for the help!