To save you the stress and struggle of trying to sync your Zune collection to the Xbox Music cloud on your phone/Windows 8 tablet, perform these simple steps on your W8 PC (won't work on others):

Settings>Preferences>Switch off Music Pass Downloads>click on the album you want added to your cloud>it will be added without being downloaded to your tablet>universal access to said album

This saved me from carrying two devices around with me everywhere! Sound off in the comments if you have any questions or if it works or doesn't work!