Glenn W makes a good point about the point.
Seperating to get more fat to render is a good thing, and as I've mentioned before, you can cut the end off it at the start of the cook to get the point to cook faster as well.
As to cooking temps and the smokering, I like to start off with a cold brisket right out of the fridge. This causes my smoker to take a while to get up to temp, but I get thicker smokerings this way. (Also, I hear that briqs give thicker rings than lump.)
I don't trust the wsm OE gauge, and even if your's is accurate, I suspect it will start reading low in the near future...at least all THREE of mine have. It's ok though, cause it's better to measure in the stream of circulation anyway. After that ramp up, I like my Maverick probe, hung just inside the dome vent, to be in the 235-250 range, but if nothing is on the bottom rack, 250-265 would probably be just as good or better...probably need to just check the water pan a little sooner.
Every brisket is different, and no matter what you do, some are gonna be different than others, whether in flavor or texture. That's why the pros inject with stuff a lot more potent than beef broth. As long as your tasters are happy though, you should be
as well. That's what counts.