Well it looks like you pulled off a good smoke..
As for tri-tips, they have a wonderfull beef flavor so you definately can cut back on the season. I have gone with just kosher salt and fresh ground pepper and it was excellent. I have also addd some rosemary and thyme by suggestion of another member and it was great too.
For the smoke, I do mine at about 275-280 from start to finish. Beef needs to be kept med rare ort below for my liking(unless I'm doing a chuck or brisky). I like to take mine to 140, shut down the heat and let it coast up to 145 in the remainder of the smoke. I use my GOSM gasser for tri's just because of how fast they cook..
I lightly tent it on a cutting board for 10-15 minutes.
For slicing, you want to start at the blunt corner and work your way into the roast. you should come to the long points at the same time with your knife..
Here's my first one..