I guess the best thing is to just have several options. Only negative for me is I have to keep my Lion install around just in case something goes wrong. I'll have to play around with the EFI method some. Maybe setup a backup Mavericks drive instead.
The Lion drive mentioned in my guide actually is just for the execution of the bless command in case you need it. I just noted it because I plan do release another guide on how to install and set up Clover, which I think is a better option than chameleon (another point of view).
So actually you don't need a Lion drive (although it's nice, as it comes with a Finder). A Snow Leopard install DVD would already be enough (even a Tiger on should work).