Why is it that on every other post I find a suggestion or experience to machine brake discs, the discs should only be machined if
1 they are allowed to be machined - no fancy slots etc
2 They will retain their minimum recommended thickness after the job.
If you have only slight scoring then just deglaze with rubbing sandpaper and install the pads, the slight ridges will be adjusted into the pads.
To ensure maximum bite from brakes and long service life from pads and discs, always "burnish" the brake pads after installing this is done by driving the car gently and very gradually applying brakes in easy movements - not one single mash.
This makes the brake pads bed into the discs and get properly burnished ready to use, if you apply solid brakes right after installing new pads, the pad will turn to something like coal and give no brakes for their life and also score out the disc badly.