I've prepared tri-tip in this way before without cooking it sous-vide and it was perfectly delicious, so if you don't have an immersion circulator, I've included cooking instruction using a large cast-iron skillet instead.
Step 1: Preparing the rub
Simply measure into a bowl, and mix:
1 tsp paprika
1 tsp garlic powder
1 tsp black pepper
1.5 tsp sea salt (I prefer coarse ground, especially if the meat is going to be grilled)
2 tsp ground coffee
I made this amount of rub anticipating using it all to season a tri-tip that was a little under two pounds.
Step 2: Preparing the Meat for it's Hot Tub Bath
I like to trim all of the fat that I can off the outside of the roast. This is an especially important step since I'm preparing my meat sous vide, so the fat won't render the same way it would in a pan.
Once your meat is trimmed, pat it dry with a paper towel and apply the rub using your hands. Cover the entire roast using all of the rub, pressing it into the meat.