I really forget the warmer temperature (i think it is 160 F) but like someone mentioned on here if you wrap it in butcher paper, then wrap it up towels, then put it in a cooler (without ice of course) then it does the job. You do this after taking it out from the smoker when it is finished.
And definitely yes, keep it wrapped at all times when warming.
1. High quality brisket to us is taste and tenderness. Taste is beefiness, smokiness (not too strong, but present), right amount of salt taste, and a good bark (here you will have opinions, between "soggy" bark and "crusty" bark). Tenderness is it must bend on the finger and you can eat it with just a fork.
2. For us low-slow is for offset (ie; traditional bbq pits) and fast-high is for gas powered (ie; Southern Pride Smokers). Reason is gas powered smokers create a lot of air/wind, thus drying the brisket faster than a traditional offset smoker. The verdict is that offset smokers make a better product (ie; because it's low-slow, which you can't do with gas powered smoker).
3. I believe we are warming at 160 F but don't remember.
4. We don't do tented foil, but there are lots of youtube videos claiming otherwise.
5. Flame/coals, don't know enough about this.
6. We don't have any special equipment other than really good gloves to carry hot brisket around when wrapping.
7. You can cook the trimmings separately and use them for sandwiches (since you don't need a clean looking slice) or use it in beans. You can also grind it to create products like sausages or burgers. See this video https://youtu.be/H-_ok8WGb4k?t=236, look at how thick the trimmings are.
I own several Texas BBQ restaurants. We have a pitmaster but here are the things I know:
1. Not all beef/cattle are created equally. You must start with a high quality brisket. Just because it is a prime grade brisket is not enough. We tasted brisket from many farms and we centered on Creekstone Farms.
2. Not all smokers are created equally. Test the extremes including low-slow (12-15 hours) vs fast-high (8 hours). We found offset is good for low-slow, but gas powered is better for fast-high.
3. Not so secret: you must rest the brisket for 12 hours in a warmer after it is finished cooking. This gets the fat rendered inside, so you can get those grooves / mountains and peaks within the meat. This also achieves the most tender brisket.
4. Before wrapping with butcher paper, we put beef tallow on the brisket. This creates a juicier product for us.
5. Injecting and/or putting brisket slices in broth never worked for us. Instead of tasting like juicy brisket, it tasted like "brisket and broth".
6. We trim a lot to get a more even brisket with consistent height, and use trimmings for other products. Consistent height means your flat lean side won't dry out by the time the fatty point side is cooked.
Look into how you look visually and how you speak and your behaviour. Are there things you do that [incorrectly] raise a flag for other people? Like someone mentioned on here, get detailed feedback.