Yo Coach, I used to be the king of marinades. Fifteen years ago, I used to marinate everything including green (fresh/uncured) hams, pork shoulders and briskets. These big pieces of meat would marinate up to 48 hours. Most of my marinades were highly acidic and contained various fruit juices as well as Coke or some other cola based soda.
Now what I am about to say might ruffle some feathers and this is my own personal opinion, but it is based upon NUMEROUS trials and years of experience using marinades. Marinating large pieces of meat is a waste of time and marinade.
Marinating smaller pieces of meat is fine for flavoring and tenderizing, but it will not tenderize a large piece of meat. The deepest penetration I have ever seen using an acidic marinade is about 3/4" deep and this was after 36 hours soaking time.
By the time the marinade penetrates this deep into the piece of meat, the outer portion of the meat (about 1/4") has become mushy from being tenderized. The marinade does flavor the meat, but IMHO for tenderizing it is highly overrated.
So my "advice" to you is to forget the marinade on the brisket and use the rub only. If you want to experiment, you might try injecting the marinade you want to use in the brisket and then rub the brisket. I would not let the brisket sit more than six hours though after injecting it if the marinade is highly acidic.
Beers to you,
Juggy D Beerman