Thumbnail effect

I am trying to make a thumbnail effect where the size and alpha of the thumbs varies by its position. I am using my own variation on the infinite menu. What I am trying to do is have the thumbs increase in size and alpha the closer it is to the middle of the stage.

Kirupa Infinite Menu link for reference.

This sounds like it should be easy to do using the ‘setProperty’ command, yet I have failed each time I do it. Basically, the stage is set up with buttons inside the thumbnail movie clip that link to a main image holder.