Your far easier method of making weed coffee would be to take some cream and extract the THC into THAT- quite simple- a couple grams ground bud per fluid ounce of cream, in a mason jar, simmer immersed up to the shoulders, lid ring on but not tightened fully, ~45 minutes, agitate occasionally, strain through a metal coffee 'perma filter', return to the mason jar, store in fridge until needed.
Use a tablespoon or 2 per cup of coffee, stirred in as your creamer. Mmmm. If you want to get fancy, add a cardamom pod (Turkish style), a cinnamon stick, or a vanilla bean to the cream/weed mixture as it simmers. Be warned, this is an efficient oil into oil extraction method and the flavor comes out INTENSE, so use very little of your chosen spice, or omit it.