shall we just put it in the box I gave you for now ? If I decide to try and get clever I can have a stab at it later (I'm hoping to have snagged a cheap pillar drill by next week so I can drill my own enlosures).
Remind me again about stepped drill bits : was it 13mm you said I should find one that does ? Many seem to have 2mm steps in even increments . . .
The 3-14 is a cone drill, so will be a pain for most things - you'll have to guess if you've got it right. 10mm is too big for the smallest hole.
From there I'd suggest:
MC 1m High Speed Steel Step Drill 4mm To 12mm
XT314 High Speed Steel Taper Drill 3 To 14mm
So the step drill for most things - you'll be able to count the steps to know how big a hole you've made (fer instance, on my step drill it's 4 steps for a mini pot, 5 for an LED, 7 for a normal jack, 8 for an isolated jack and all the way through for a footswitch. Then the cone for opening out DC jack holes.