Thanks SteveCK. I'm currently using a 6 cfm blower. I'll try it on max = 75%.
Just finished reading your micro damper post. From one engineer to another, bow! Very impressed!!
This is a small, thin plate of steel riveted onto a pit barrel cooker. Really simple.
https://goo.gl/photos/WngqfmvPFZYV6C4b8
Apologies, I can't seem to get the image to imbed in this post.