well, I actually wound up getting the tray, for my mes analog, I just pulled the little drip tray out of the bottom, and there's enough airflow through. you put pellets of your choice into the tray, (or you can mix pellets and chips, but no more than about 50% chips. if I use chips, i put a layer of pellets on the tray, with the chips on top, but still not over the sides of the channels. to be honest, I don't bother with chips anymore) light one end of the pellets (I use a blowtorch) until it's a bright red coal, about the side of the first joint of your thumb. stick it into the smoker, make sure your temp's right, put your meat in, make sure the temp comes back up properly, and then leave it alone. I've gotten a full 14 hours of smoke out of the tray, but if you need more smoke for a shorter time, you can light both ends of the tray, or if you want just regular smoke for a shorter period, you can fill 1/3 or 2/3 of the tray instead of 'full'
I had to do a small hack to my mes, in that I didn't have a 'good' place to set my tray, but my model has a nice hollow in the center of the element, so i got a piece of decorative 16 gauge steel with cutouts, cut it to size, and slide it in under the element, it rests on the supports, and holds the pellet tray neatly.
not sure if this answers your question. btw, the pellets i use are the lumberjack brand. I get them from atwoods, but the smoke is clean, and the flavor's good from them.