Don't know much more about brisket than Jay, but would be glad to ramble on what I've had the pleasure to experience....
My brisket cooking got much better when I got more selective on what I picked to cooked. I like prime grade, but have had good results in being very selective on choice briskets. The better the grade the higher finish temp seemed to be, not that I really worry about a certain finish temp. Seems to me, that the higher temp I ran my pit at, also resulted in a higher finish temp....it just got done faster though.
As far as the fat seem, I remove the fat cap from the point, and try to remove some of it from the seem(to expose the point). Not a proven fact, but by removing fat cap off the point, I think you get more of the seem to render, and you'll never have the concern of drying out the point. So I basically have the fat cap off of 2/3rds of the meat/point on the bottom, if that makes any sense.
I too love Butchers injection, at home, I use the original at about 2/3rds the strength and add a tablespoon of beef base and a tablespoon of Worcester sauce. inject cross grain at a 45* angle while pulling the needle out. I don't inject the point either.
I do wrap with foil for an added flavor, but I like to do it later then most folks and I want my marinade warmed up first. I use a modified "Rick's Sinful Marinade", you can google that beer marinade. Make sure you use a full body beer, I prefer Shiner's beer.