I'd bet a feller could run across all types of concoctions and recipes. I've gotten to the point of using Butchers injection, just because it is easy and David is trying real hard to raise them kids...LOL!
If I was to make up something at home, I'd try 2 cups of broth,1/4 cup Worcestershire sauce, 1 tsp onion power, 1 tsp garlic powder,1/2 tsp cayenne powder. I keep a container of beef base in the frig, so if needed I could add a tsp or so for the real prime beef flavor or even make the broth with water.
Now pay close attention to the part of the recipe that calls for powder...you want to be able to add flavor and not chunks of seasoning, just trust me on that part.
Small amounts in a 1" checker board pattern, I would guess around 1oz per pound would be what you might use. Heck, if you have a little left and your gonna rest that brisket in foil for a few hours after cooking?...you might just add any leftovers to your foil.
Good luck!