I have an MES 40, sportsman Elite. It has the side loader you twist and drop in.
I have used both chips and pellets, and combo of the two.
Pure pellets burn quicker, and create a thick smoke, but only for 45 min to an hour.
I have bypassed the loader, and placed a combo in the tray and slide it back in manually. Half and half, split down the middle. What I think happened, is the pellets lite first, heavy smoke, then the chips carried it a little longer. Still playing and need to verify mid smoke.
But the combo worked the best. Apple chips and Mesquite pellets. Used on a brisket. 4 loads over 8.5 hours, worked great.