Ah, Ok...MES runs pretty humid from I hear...good for smoke reaction, but bad for drying out the meat later on in the smoke with meats taken to high finished temps. I've been advocating a wet-to-dry smoke chamber method for about a year now. High humidity keeps the meat's surface fibers loose and porous, which smoke likes, but as the cooking progresses, this loose, porous surface lets moisture evaporate from the meat at a higher rate than if a dry smoke chamber is used before internal temps get too high.
I don't foil much of anything anymore as result of using this method, and I'm not sure what you might get for results in the MES, but a lot of folks do foil after the 160-170* range...you may want to go that route, too.
Here's some info when you time to read...a search from my signature line link "Wet/Dry Smoke Method"...look for Pork Butts or Picnic...the picnic smoke was just finished yesterday...there are plenty of other cuts I used this with, but the shoulder cuts are what you're working on right now.:
http://www.smokingmeatforums.com/ne...sort=relevance&order=descending&Search=SEARCH
Also, to better explain why humidity effects smoke reaction so much, among other things...lots of research in this:
understanding-smoke-management-updated-5-18-13
EDIT: man, I gotta slow down! I just realized I posted this link twice now....LOL!!!
You won't have a full understanding of all of this in one day, and won't be able to apply much, if any of it, to your smoke right now, but in the future, you can be better prepared if you wish to use this method.
Eric