Tune-o-Matic Piezo install??

[CondeZL]

I have a Les Paul with P90s and I would like to install a Piezo bridge on it. Do I need to drill the wood or just the pickup cover? Also, would it be possible to use a tone pot as a blend (0 - full piezo, 10 - full P90, both pickups in between)?
I am considering to import the Schaller Tune-o-Matic.

 

[kramersteen]

Re: Tune-o-Matic Piezo install??

I would go under the pickup but see what others think.