I always used dry rubs on my brisket and ribs. A pal kept saying wet marinades add more moisture. I tested it on a pork butt last month. The meat cooked up softer and held flavor better. The liquid helped the spices sink in deep. Now I start with a marinade and finish with a rub. My BBQ has never been this good before.
I used to guess but now I rely on my thermometer and it's a game changer.