Happy to stay in touch. I haven't build one of these in a long time. My website and email address are in my bio here on HN.
To answer your question, yes, that's a piezo pickup, if I remember correctly. I don't think I had any kind of pre-amp. I wired it to a 1/8" stereo plug and then connected that to a very small portable guitar amp. It was all very rudimentary. A very distorted sound. I don't remember grounding to be a problem but I played the slide version of this with a slide made from a galvanized pipe, rather than glass.
To answer your question, yes, that's a piezo pickup, if I remember correctly. I don't think I had any kind of pre-amp. I wired it to a 1/8" stereo plug and then connected that to a very small portable guitar amp. It was all very rudimentary. A very distorted sound. I don't remember grounding to be a problem but I played the slide version of this with a slide made from a galvanized pipe, rather than glass.