I've done three briskets in my #2 now and every one of them has come out unbelievably good. I have brined all of them and I think this is an essential step. I can see a physical difference in the meat after brining for as little as an hour.
I have an old frothing pitcher that I use for water... I fill it half full and stick it right next to the firebox. I never use foil for anything other than to cover the lid of the firebox, the floor of the firebox (with a few holes poked open), and the floor of the smoker.
I'm surprised to hear that you're getting a bitter creosote flavor... I suspect you're correct about the wood combusting. Otherwise, are you just putting the brisket in and leaving it until the IT hits 190 without opening it during the smoking process?