I haven’t done a 3 hr/lb butt, but I’ve had a couple go 2 hr 15 min/lb
I start and finish at 225⁰ and have been very happy with the results for smoke, tenderness, moisture, and flavor.
I’ve had my share of PBs cooked at 350⁰ for 4 to 5 hours and I now say no thank you
But hey, to each his own whatever floats your boat.
If it’s good enjoy it
Glad you like your new smoker