Organizing a Blog Tour or "Hi, I'm Julie, your cruise director"

I volunteered to organize a Blog Tour last night.

I know I have people on my flist who have done this.
I was wondering, is it more effective to start with a small group and blog on each other's blogs? Or to take it out to bigger public blogs like a roadshow?
Or both?

My tweets

• Mon, 16:14: State of the Sooky http://t.co/YCxVvuk7
• Tue, 11:46: I am organizing a Blog Tour for The Literary Underworld. If you would be willing to host this motley crew on your... http://t.co/mjMEnfQV
• Tue, 11:54: Organizing a Blog Tour or "Hi, I'm Julie,yo cruise director" http://t.co/Rvlp4vgp