Hope this is helpful. This is the drill bit sizes I use, and in some cases I have the mm equivalent.
Drilling hole sizes:
footswitch: 1/2 (12.7mm)
pots: 5/16 (7.9mm)
5mm led metal bezel: led bezel: 5/16
5mm led plastic bezel: 1/4
3mm led metal bezel: 1/4
toggle switches: 1/4 (6.35 mm)
jacks: 3/8 (9.5mm). The Lumberg and Asian ones measure 8.7 and Switchcraft measure 9.2 with calipers
switched DC jack: 7/16-1/2 (note it's slightly above 7/16, so need to drill then enlarge until it fits) (11.1-12.7 must be 12)
low profile DC jack: 5/16
I've said it many times before, I'll say it again...
Get yourself a hand-reamer to go along with your drill bits. Helps clean up the edges of the hole and can finesse a Goldilocks moment for in-between-drillbit-sizes.