Yes I use a Maverick Probe and also put another Poulder probe that I have in another area of the chamber. I am very careful/ accurate with all of my temps. I typically have 2 Mavericks and my poulder in use for every smoke, plus I check the ITS of all of my meats before pulling with my Thermopen and/ or thermopop intant reads.
Have you checked the actual temp in the MES with a calibrated probe? MES readings are known for being inaccurate.
Also keep the vent open.
My MES actually runs hot, and with 2 of the spatchies I have done, I let it run hot which put my mav probe at 289 for most of the cook, and even those ones ended up with less desirable skin.
just wondering if anyone else has any other tricks or secrets to getting good skin if I want the full cook to be in the smoker. The other thing I have been planning to try is to pull it at some point after it has gotten some smoke, and throw it into the oven at a higher temp to crisp up the skin.