If you have a MES w/ digital read out it cycles the element when it reaches the set temp or shuts off the power when it runs out the clock.
I think that the best thing for you to do is, Once you figure out your smoking times set the timer for as close to the figured time as you feel comfortable with.
Don't know what you are trying to achieve, But The big thing is once you figure out how to turn it off ,
MAKE SURE the temp. of the meat does not drop below 140 degrees before you can get to it.