That dry rub sounds interesting! 200* chamber temps should do fine, being it's not injected...should cook slow enough to get a tender slice when finished, though towards the end, getting 190* internal with 200* chamber temps could take an eternity (the temp differential is too close), so you may want to bum,p temps to 220-225* after reaching about 175-180* internal to compensate for the close temp differential.
If you do a brine, I would suggest reducing the salt in your rub to a total amount applied of less than 2 tsp...depending on salt concentration in the brine of course. If the brine is 5% salt, a 1-hr brine won't add a lot, but 10% or more would push the osmosis quite a bit faster, and yield higher salt content in the meat. The sugar will also effect the osmosis somewhat, allowing the meat to bulk-up a bit more.
With a larger cut of brisket (or pork butt, for example), excessive amounts of sugars (especially in the rub) can cause scorching of the meat, but you're smoking at lower temps and for much less time overall, so sugars won't be much of an issue.
Before pulling it out to rest, poke around a little for resistance, just to be sure it is gong to be tender enough. Some will be tender @ 180*, some not until above 190*. also, if you prefer a thick slice to be be tender, you may want to take it a bit higher than you would for thin slicing. Thin slices may not be achievable if you get it too tender (it will crumble and fall apart under the blade of even the sharpest of knives).
As for the cut itself, Angus typically has a bit more marbling of fat than others, which helps to produce more flavor and aids in moisture retention. The center cut is a trimmed flat muscle from the packer, which is otherwise much leaner than the point of the packer. Just keep it low & slow, rest for at least a couple hours, and it should make for some fine dining. You could do a temp-hold in the smoker or oven to allow temps to come down more slowly, as that small of a cut will cool fast, even when wrapped in foil, towels and resting in a warm insulated cooler.
If you haven't yet, you could consider adding a bit of rosemary and thyme to the rub (both enhance the natural flavor of beef very nicely), but if this is a rub you like as is, then don't fuss with it.
Have a great smoke!!!
Eric
