Has anyone tried the Schertler contact mics with ukes?

I'm curious about the Schertler contact microphones from their DYN series. They come in different types (for different instruments) and with and without phantom power. As they are a bit pricey, I wonder if anyone has first hand experience with them? If so, which ukulele/wood/size did you use them with? Are there feedback issue in a group/stage setting?

Link to the guitar one: https://secure.schertler.com/en_IT/shop/pickups/dyn-g-p48

And the universal model: https://secure.schertler.com/en_IT/shop/pickups/dyn-uni-p48

I'm not even sure which one would be most suited for a ukulele. They cost more than most pickups, but they would require not modification of the instrument and could be used with multiple ukuleles.

They look interesting ........wondering where you place them on the ukulele?

I haven't tried the contact mics, but I have a Schertler Resocoil on my Pepe ukulele and it is pretty good. Of course, for the price, it better be!