Time For Thumbnails

Alright, I've decided to take the highroad and challenge myself. I'm going to be animating a video and setting it to tracks of music. I'll be spending time creating animation thumbnails and then pairing music to the thumbnails to determine how long each section will be between the two and so on. I'll be doing this between every picture, again, and again and so on. I'll be doing all this until I have a basic reference for what I'll be animating. Right now I'm brainstorming ideas in a thumbnail journal of sorts. When I have a more comprehensive idea of what I'll be drawing I'll post a couple of thumbnails from it. What size do you guys think the thumbnails should be? Full 8/11 size?