If I understand correctly what you're saying, I did have a similar problem to yours.
I search all over the place in order for the syncing to work correctly, then a friend of mine showed me this google site, and now everything works fine.
I don't know where he found that link, but its not under any of the google tabs.
It fixed my problem though.
Tell me if it works.
Similar problem here. I can select the delegate calendars within iCal, but it simply doesn't sync any events for the delegate calendars. I'm also returned an error if I try to manually subscribe to the calendars, e.g. using a direct link from the Google calendar settings.
Either way, I think it's all related to a known block Google have implemented to deal with an iCloud conflict. Keep an eye here for a solution...although it's been several months already obviously:
NB. The iPhone select solution will get things rolling on any iOS devices.