Hi Tomzera,
There is a file named "AstroEQ-DIY-Holes.pdf" supplied with the DIY design. This shows the location of all the holes.
You should be able to drill most of them with a 1mm bit, though ideally a 0.8mm bit should be used for the USB port. The large mount holes will need a 3.2mm bit, as will the ones for the 12V socket and RJ11 support holes. The USB mount holes are 2mm.
Hope that helps.