I don't have my Ventus so I can't measure where the hole is located. The location is not critical however. From the fully locked position, pull the airbrake handle aft so that it is not locked. From this position, pull the handle aft gently to where you just start to feel resistance against the airbrakes. This position is the sweet spot. If you don't have a hole, another option might be to cut a piece of small aluminum angle to the correct length and use this to block the airbrake handle open to this position.