Ok I just finished installing and my testing.

conclusion was I couldn't boot from guid partition because the first disk always read rdisk0s2
And sofar The only way to make the first partition read as rdisk0s1 was to use mbr. at least It still has efi installed.

Maybe somebody can work out the guid install and post it.

I also noticed that during -s when booting from disk you couldn't use sudo, su or passwd .

but i found a NEAT trick, as the install on disk is in its last minute get ready for the countdown to off, as it counts down click the utilities and terminal. an now you can do you fdisk -e /dev/rdisk0 ........... and set the boot partition as active.

I also tried the AppleUpdateDone touch, but it didn't seem to work, as I still had to passwd change and su.

one major flaw is my 3800x2 only has one core in system view, im not sure if it's the 9.2 or just a flag for stability, but I think when I workout where the cpu=1 is hiding it will go back to normal.

Also Need another few fixes will prob try to load with -s on first boot next time and see if I can get around the passwd setting, and remain as root, using the TOUCH .......AppleUpdateDone.

So good luck im sure in mbr mode most should have no troubles.

If the mod could start a thread about using guid partitioning and make it a sticky we may work it out faster. It seems to have worked for some.