New Years brisket, great idea! There’s a lot to unpack in your questions, giving the type of smoker you have and some pictures could help provide more targeted advice. But I’ll do my best to give some general advice.
I have a Traeger, and i just throw it on the grates and let it go, usually at 250-275. You can do the lower temps, but my opinion and many others, is that 185-210 doesn’t do anything for you but extend the cook dramatically. It could also be dangerous if you’re injecting or puncturing the whole muscle. I’ve never had a problem with burning? How burned does your brisket get? Is there a heat deflector over your pot? You could wrap your brisket in butcher paper or foil once IT of the flat hits 165ish. That would help with your burning problem, it also stops smoke hitting your meat, though you could wrap with smoked beef tallow to help bump flavor. Not sure how you did this before, but some people think that the fat cap should always be up, but that layer of fat should be where the most amount of direct heat is hitting your meat. On my pellet smoker the fat is pointed down because that’s where the heat is the most intense. For my offset the fat cap goes up.
On the rendering question there is more than a few things happening with a brisket, you have the internal rendering of collagen that starts happening at around 160 that makes the brisket flat moist and tasty, this is the happy zone where the magic happens up until that final probe where you get the butter consistency we all strive for, usually between 200-210 IT. Then there is the denaturation of the fat and proteins that starts at lower temps, I think around 130? That’s when your fat cap is dissolving and basting the meat. Not all fat will dissolve though, trim your fat down to about 1/4 inch and trim off any hard fat, or Deckle too, that won’t render or be tasty.
On the seasoning question, most would highly recommend trimming and seasoning the brisket 24 hours out, that lets the salt absorb into the meat. I normally use about 1 teaspoon of Kosher salt to each pound of meat, others use less or more. I recommend starting with a simple Dalmatian rub (Equal parts K. Salt & Cracked Pepper) or Salt, Pepper, Onion, Garlic rub (SPOG). SPOG basic recipe would be 2 tablespoons each K. Salt and Cracked Pepper, 1 Tablespoon each Granulated Onion and Granulated Garlic, you could also put in a Tablespoon of Paprika for color. I’ve never tried mixing Lowry’s in with a a rub, but I think it has a high enough salt content that you’d probably want to use it solo. There is an abundance of off the shelf rubs out there that are really good, just read the ingredients and see what catches your attention. But, I’ve become really happy with just the salt and pepper.
Last bit of advice, you could cook this a day out, then reheat in oven. There are lots of threads here on how to do that. I don’t like doing that as much. If I did a brisket this new years at 225 cooking temp, I’d start the night before, around 8 or 9. That way I know It’ll be done before the next evenings festivities, then wrap it, after letting it rest uncovered for about 20 minutes inside, and stick it in a cooler with towels until it’s ready to serve. Don’t start it the morning of, that’s just rolling the dice.
Here’s a Brisket I posted a while back. Sorry, not a lot of detail in the description, and I did smoke this one at 220, but in the picture you can see fat side is down towards pot, and the point is towards the hotter part of my grill…. Not that the second part is obvious.
Greetings, the fall weather, and posts here, has kept me motivated for soups, stews, and Chili. But it’s warm enough where I am to keep smoking. So I went with both! One of my Daughters turned 5, so we had a party and the kids had cheese pizza dressed as princesses and I had smoked a good...
Good luck! I hope this helps, if not, give a bit more details and we’ll see how we can help more!