Fin Mounted TE Prob vs fuselage mounted TE prob

On my LS-6 I have a small TE Leak somewhere between the bottom of the
Vertical Stabilizer and the TE Probe that's located on the upper
leading edge of the Vertical Stabilizer. The leak is most likely where
the tubing connects to the TE Probe. I think that I would need to cut a
hole in the Vertical Stabilizer to fix it! UGGHH!!!

This Fuselage mounted TE Probe would be a perfect fix for my situation.
My questions a How do you know where to place the probe on a
particular aircraft? How come nobody figured this sysytem out sooner.
Are there any down sides to this system??