A couple of notes.
1) These are completely unsupported. (Hence this thread being in the discussion forum)
2) Cornerstone builds are roms - not updates to a nightly build. Saying something like "I'm running Cornerstone wingray #17 with wingray nightly #90" is pointless. You only need to install cornerstone and then the google applications.
3) Always state what device and build # you're using - this thread is for 4 different types of Xoom on potentially different build numbers - AVOID CONFUSION. Not everyone knows what device you have.
4) You're welcome to say your experiences about the rom here including issues, however do not be insulted if I never reply to issues or bug reports. Remember these builds are unsupported.
5) Builds can be attained from http://goo.im/devs/teameos/roms/cornerstone
6) Please don't file bug reports for cornerstone.
7) If you're using cornerstone, please don't post in the official nightly build threads about your issues. This only confuses people.