I cooked half a dozen briskets or more at 225 with middling results (to internals always above 190, wrapped/unwrapped/rested/you name it).
I then cooked one at 285 or higher accidentally one time (UDS temps got away from me while I was woking), and I have never looked back. Don't mean to hi-jack - your cook looks amazing. And I know with pellet poopers, you gotta cook lower to get smoke...
On second thought, I'm totally sorry for the hi-jack.
Enjoy your new cooker and keep us posted on the final output!