Basically what BakersDozen said. It's a really quick way to drill all the holes without swapping bits. Mine goes up to 25mm, so on the Valvecaster I could drill everything with the one bit, including the tube socket.

I somehow managed to both bugger up my template for this one, and also mislabelled the pot hole sizes - so I drilled the first two to be almost the same size as the pot washer, and the switch and one of the LED holes is in the wrong spot.

I realised the pot holes were too big because they looked wrong, and even though the washer covers them it's not a good look if I ever end up giving it to someone else. The LED and switch being out is obviously the main reason I'll have to buy a new box.