I started drilling on the bottom side near the toe so I wouldn't get too close to the toe edge where it slips into the boot, I then drilled out the holes on the heel. Be careful where you drill on the heel as you do not want to drill through the thread that holds the rubber strap on. After this I went through the orange side so I could better gauge where the screws would be placed after mapping it out with the marker.
I drilled a total of 25 holes on each sole. Make sure you focus on where your highest wear spots are and put some extra holes in that area. Check your old Korkers for where the studs are most worn out. After drilling I used a Dremel to clean up the plastic around the hole. I used Round head screws so I chamfered the edges of the sole so the screw-head would sit down in the sole a little bit. I would suggest using Truss Head screws as opposed to round head as they are flatter and a tad wider.