I can't really comment on the Birchwood Casey Plum brown except I've used it before and I prefer the Laurel Mtn Forge Brown. You don't have to heat it (for a brown), it's its own degreaser so you don't have to worry about handling the piece with gloves and I've heard it's very durable. My hawk turned out darker than it appears in the photos. But when the instructions say 3-24 hours for the first application, I would go with the full 24. Maybe it would work faster on the smooth steel of a rifle barrel, but I've found hawks take a little longer than I expect to finish or patina....I'm not a patient man when it comes to projects, but I'm getting better.
As far as the wood goes, my tastes keep changing. I used to like the deep reddish tones, but for hawk hafts I sort of like the plain hickory with scorching and oil...the solution is to have some of both