Drill to pick:
Measure 16mm up from the top of the keyway then 16mm towards bolt.
Use a 6mm hard-plate drill bit followed by a flat ended 6mm drill bit, the flat ended 6mm drill bit will completely open up the hole without damaging the levers. (You can make a flat ended drill bit for your tool bag by grinding the tip off a hard plate drill bit).
Drill for the stump:
Measure 16mm up from the top of the keyway then 20mm towards bolt. Consecutive holes may need to be drilled to remove the stump, especially if your measurements are slightly off. Use a 6mm hard-plate drill bit.