I don't bother with check raise bluffs... I don't think you can win with them at a microstakes level, because people (if they arent terrible) are usually playing ABC poker and will only bet if they have a hand. At Phil Ivey's level, any bet could easily be a bluff, so a check raise bluff is much more profitable. The only time I'm ever check raising is with the nuts, or as close to the nuts as possible.
As for going card dead in the middle of a tourney, you shouldnt be bluffing in the middle of hands to take down pots, you should be bluffing at the beginning preflop and from position. You should be constantly checking your M (The number of table rotations until your blinded out), how close the bubble is, and how the other players are playing.
You should do your best not to raise with nothing, but I think its better to be bluffing a medium stacked tight player in the BB with something like 78o and chancing the fact that be might turn over pocket kings or queens than to simply get blinded off and lose fold equity.
Maybe some people wont agree, but I think its best to keep it simple near the bubble, there's less of a chance of something going wrong such as if you're bluffing in the middle of the hand, and your opponent turns over something A9o... something he would have folded preflop if you shoved all in then with K10o...