Well, you don't want to lower the smoking temp for a couple of reasons. For one, if it is too low, it will take to long to get the meat through the "danger zone" which is when the temp of the meat is between 40° and 140°. The other reason is going low below a certain temp tends to dry out the meat. You don't want to try to smoke anything that has not been cured below 225°. You'd be better off to go "hot and fast" (270° to 325°) but I don't think your MES is going to do that.
Smoking, for better or worse, is a participation sport. When most people do an overnighter, they just check on the smoker several times throughout the night or stay up with it. There are not many smokers that you can load up and walk away from. Most of the ones that can do that are very expensive like the Stumps or the Backwoods..
The exception is the UDS, like the one in my avatar picture. It, and those like it, will run for 16+ hours on a single load of fuel, are very moist cooking environments so it makes the need to mop/spritz somewhat debatable, and are very stable temp wise..So . . . you could always build a drum.
With an MES, I don't see how you are going to get around monitoring it and replenishing the chunks/chips every once in awhile. But the effort spent smoking something that long is usually well worth it.
Dave