I think Ron's covered everything pretty well here, but if you do want to email me with more specific questions, the easiest way is via the contact form
on my band website (saves my email address being gleaned by spambots).
The link to the diagram showing how to wire the footswitch for tap tempo is here
. The only difference to that with the G Major is that you need to use a latching footswitch, not a momentary one, for tap tempo (momentary ones send double signals and it gets confused). Also, I built the resistor into a custom TS-TRS cable so I could use an unmodified footswitch - if you're not comfortable doing minor soldering mods, I could make you one up, although as I'm in the UK there are probably cheaper options!