First, thank you for writing the guide Tony.
Unfortunately I get stuck on the grey screen with spinning lollipop of death. I waited 45 minutes and nothing happened so I assume it's not going anywhere. -v is useless because that part goes well and then it goes on to grey screen and after a while the lollipop appears. I tried maxmem=8192, GraphicsEnabler=No, -x -- no dice.
Quick Google doesn't show me any posts about this problem but then the beta has been out the whole two days, so it's understandable.
Anybody got hints for me? Stats below in signature. 10.10.4 works flawlessly (except the fact mouse drivers keep on pooping out on me every few reboots).