I'd agree that the main key to brisket is getting a good quality meat and a whole packer not just a flat. The Primes I have bought have all been good, however the quality in them varies a bit. I've tried Select and also Choice and the Select was pretty good and the Choice also. I do have them bring me out several to look over and/or don't buy if I don't like the look and feel of the meat. I've bought from a variety of butchers and stores, but around Raleigh, NC they are all packaged the same and in cyro bags so pretty likely same suppliers. Anyway, I have not been blown away with Prime vs the others, but a great Prime will be noticeably better. You could also go Wagyu, just break out the credit card!
I trim my Prime some, thinning fat cap and taking off some of the hard dense fat wherever it might be. I also pull off the fat above the "skin" for the most part. I would agree you are better off not trimming as much until you see what difference it can make (over trimmed one and it was just OK). Just don't dig too much between the muscles because there is no end to the fat there.
I dry brine my whole packers for around 2 days (until liquid has reabsorbed), rub em with corn oil and cover them in my 3 pepper mix, let that soak in for 6 hr or so, then smoke per forum instructions using water with fat cap down. Also, I don't wrap, I let it cool either in the smoker on off or in the oven on off. I will tent it with some foil some times if it looks/feels a little dry. Wrapping will certainly improve the moisture/tenderness sometimes, but it also changes the meat a little.
I use 2/3 pecan and 1/3 mesquite wood.
I'd agree to use the tips as a reference but try what you think you may like because tastes vary greatly.