Ya know it may have been me, I tell folks that meat is most suceptible to absorbing smoke from 100 to 140 degrees (IT) which I have read in numerous places including I believe a post by Jeff. But I also elaborate that the meat will still take some smoke but at a diminished capacaity above and below the prime rate.
It is my understanding that the meat must be warmed for the pores to open to accept the maxium smoke absorption which I can completely understand, and somewhere around 140 to 150 these pore start rendering or giving off fatty fluids which inhibit the smoke absorption, the higher the temp the more rendered. Plus there is only so much room to add smoke, when there is too much, is when people start shouting creosote even though its only too much smoke.
AMPs was engineered and designed to allow for the max. amount of allowable smoke to be used without over smoking. I think I said that well! I serious do not believe that an AMPs when used as directed could ever over smoke a meat. It is a small continious smolder, if you are smoking both ends at the same time I still doubt it could over smoke. Now if you would like less smoke flavor on your meat load less in the tray.
Smoking a butt for 20 hours of cooking, I just don't see the point personally, but many folks have the idea because of what they have seen someone do that because the wood was smoking to cook the meat that the smoke was needed. To each their own, its the nice thing about smoking. You learn to smoke and bend your smokers will to accomplish the finished product you want, the way you want to cook it. That way we get plenty of experience, to gain that much needed knowledge and become wise enough to not need foils, digital thermometers, etc., and still know enough to be able to use them when needed.
I am buying chips, chunks, splits, or pellets and I'd just rather not use what I feel is not needed. Thats why I own and use AMP's when I am done smoking I can close the vent on the smoker which removes the oxygen as well as the draft thru, the AMPs shuts down and I can use that remaining in the try on my next smoke if I didn't time it out right.
To the topic, you can not over smoke with an AMPs even if you tried, the available oxygen and the available inline fuel would not support it.