Important note: Don't try to cut the hole for the tweeter all at once. Go slowly, stop and check your depth. You do NOT want to cut the vinyl out while you cut the plastic!
Step 5: Finish your cut of the plastic, and peel it off the vinyl, like so.
Step 6: Using a sharp knife, cut slits from the center of your pilot hole out towards the tweeter hole.
Step 7: Push your tweeter through the vinyl until it's flush the way you want it.
Step 8: Secure the tweeter using a hot glue gun, or however you feel like doing it.
And this is how it ends up:
