Brian Y. Marsh
You can read more details about the installation over at my blog!
This method saves you a lot of money from buying specialized, third-party focusing screens. At the time of this posting, the Eg-s Focusing screen for the 5D Mark II is only $35 (link below).
You can purchase specialized, third-party focusing screens that are made-to-order, from only a few online retailers. But prices for those screens are $90 +