I have a MES40 which is very similar to yours. I am no expert but this is my experience... I had my butcher slice up some london broil for me a few days ago set at #3 or so on his slicer. Marinated with a little soy, pepper and a little "very very teriyaki" marinate.
Anyway, I set at 145, and while so cold outside smoke does appear at the start of the process for added flavor if that is your desire. Open the top vent all the way. It took about 5 hours, but check after 3 because there are hot spots and some pieces will dry out faster than others, and thickness will affect time. So some will take less time to be done - though opening the door to pluck out the done ones is not really a crime. For the most part it came out tasting great.
I found chicken is hard to slice so thin (and my meat store is not allowed to run raw chicken through the slicer). Yet my dog loves chicken jerkey. So I found it takes a good 6 hours at 150 to produce a chewy product for the dog. For the dog I marinate for an hour in a mild little salt and sugar brine. Dog loves it, and it won't die from eating imported Chinese chicken jerkey.
I bought some expanded metal at lowes (just the cheap $7 non galvanized kind), cut to fit my racks, then seasoned in my gas grill for an hour, occasionally spraying with pam to build up a nice layer of burnt grease. Expanded metal works great for doing jerkey. If you do get a small sheet at lowes it is imperative you burn off the grease & cosmo that is applied to the metal before seasoning. You can't see it, but trust me it's there -only my gas grill gets hot enough to burn off the gunk.
Well maybe this helps. I am sure there are better ideas out there, but it worked for me.