I mainly followed some videos on Youtube for the X61/62 like this: https://www.youtube.com/watch?v=bcaMFkd_xSY (this one is for the X220). The X220 is a bit easier since there is a big community following for the HD mod [1]. I'm pretty sure the HD mod started from nitrocaster.
Edit: Buy some Gaffers tape too. Much easier to use to tape things down compared to electrical tape.