I have cooked a bunch of Waygu and even more CAB packers.
I find that the differences are small, with maybe one exception.
The Waygu seems to have a short window for "doneness" compared to domestic brisket. I try to stay of top of it at the end, just as I do with domestic--just a bit closer.
BTW, my first ever Waygu cook was at a comp with a CAB for backup.
First place brisket in a field of great brisket cooks.
I just did it as I always cook brisket and kept a close eye on it at the end.
Otherwize, I think if you start anticpating big changes and make big changes in your cook schedule, you will just wind up scewing it up or being dissapointed.
I would prep and cook it just like always and then "fine tune" later if need be.
Just my thoughts.
"Flirtin' with Disaster" BBQ Team (RETIRED)
FBA and KCBS Cook and Judge.
Former owner of a WSM, a Smokey Joe, a Charbroil Commercial gasser (junk), the legendary "StudeDera", a Fast Eddy PG500, and Sherman.
Now cooking with a Yoder YS640
Proud Pellet guy cooking on real wood.