I have only used the BP-100, have it on 2 basses and have been gigging with them for over 12 years. When mounted the way they tell you, it is absolutely the worst DB pickup in the world (aside from the Shadow), especially without using the Platinum Pro preamp.
1. Stack the piezo elements on top of each other shiny side to shiny side.
2. Get one of those felt pads with the sticky back for the bottom of chair legs. (supermarkets, drugstores and hardware stores have em. They are the same diameter as the BP-100 elements and are sold in quantities for only 3 or 4 bucks).
3. Stick the felt pad in the bridge wing sticky side down (E side). You may have to compress it a bit with pliers to fit.
4. Slide in the elements on the bare felt side against the top of the bridge wing. (should be tight but not too tight).
5. ???
6. Profit.
I'll try to post pictures of my setup using this pickup and my jack solution (I HATE using the jack clamped to the strings; horrible idea IMHO). I should probably be using something else but I'm kinda "dyed in the wool" about the BP-100. I've also invested too much time getting it to work but now you can benefit from my struggles and experimentation.
PS: My feedback problems didn't stop until I started mounting it this way and using the Platinum Pro (before I had one element in each wing which was miles ahead of the typical mounting but sounded a bit anemic; the above method will give you LOADS of gain and BOTTOM so turn the input of your preamp all the way down). The above method should make the pickup useable.
