I've become very adept at making the brisket you're after in my MES 30 Gen 1. It should turn out ever better in your model.
Keep it simple. If there's a lot of hard fat you can trim it down because it doesn't render very well. But some guys don't believe in trimming any fat off at all, whether it's the hard or the soft fat.. It's your choice. I didn't trim any of the soft fat last time and I thought it interfered with bark forming the way I wanted it to. The bark was a bit spongy because of the unrendered fat.
Choose a good dry rub whether it's a commercial rub or one you make yourself. I like applying a base coat of yellow mustard to both sides of the brisket and then applying the dry rub on top of that. For brisket I think the best wood pellets (since I use the
AMNPS) are either oak or hickory. Oak on its own works incredibly well with brisket but a lot of guy like hickory. You can even mix the two. I prefer to cook everything at 235° but in the MES the controller hops between 235°-250° before if finally settles down to my set point.
A 3.75 lb. brisket isn't that large so it's possible--depending on the temp you cook it at--to finish it up in about 8-9 hours. I'd definitely foil it when it hits the stall, which may not last that long in a smaller brisket. Typically you foil when the IT hit 160°. Guys had foil juice to add flavor and to steam and further tenderize the meat. I don't add foil juice anymore since the brisket renders so much fat inside the foil adding extra liquid makes some parts a little mushy to me. I unfoil when it's just about at the finish IT of 200°. Some guys feel the brisket is done anywhere between 185-203° IT. If you can test the texture of the meat at 190-195° where it should slice the way you want it to. I like 200° because there are parts I can slice and parts that are perfect for BBQ pulled beef sandwiches. The higher the IT the more it will pull and the less it will slice, or at least that's my experience. I also like to brush on BBQ sauce after I unfoil just to add to the flavor and the texture of the bark.
If you decide to take the brisket out at 190-195°, I highly recommend you keep it foiled and place it in a cooler with a towel or newspapers over it. It'll keep the brisket warm for hours and further add in the recirculation of juices and flavor throughout the brisket. Bu if you can't wait, just let it rest for 15-30 minutes while tented with foil on a cutting board, then slice and dig in.
In fact, I've found with brisket that it may not taste very smoky when it comes out of my MES but if I give it a few hours or a few days the smoke flavor starts to bloom wonderfully. Of course you can apply as much smoke as you want during the cooking process. I learned early on that too much smoke makes meat taste bitter and harsh. I always say smoke should enhance meat and not overpower it.