You can do them now if you wish. Mine's a QB, I'm 6'-1" 220lbs, and I can tell you, it was not fun crawling into the tailcone to drill those holes. Doable, but not fun. Anyway, you will be installing static ports, and you need to support the tubing going left to right, so you will need those holes. In the picture you can see my tubing in the background. Now, I only drilled four holes and used static ports from Aircraft Spruce.
