I worked on Pat's uke today. First thing was drilling a hole through the bridge, top, and walnut brace inside to accept the passage of the Piezo cable. It must lay flat under the saddle in the groove cut in the bridge. This hole wants to be slanted so that the cable is not forced into a tight bend.
You will want to make this hole a little large by moving the bit around while in the hole. I even filed it smooth and enlarged it a bit with a tiny file because the most difficult part of the operation awaits. You put a piece of thin wire down the hole you have just drilled-and then bring it partly out the sound hole. After installing the Pickup out the hole in back and securely tightening it down you wrap the wire around the tip of the Piezo cable and pull it out the hole. This is easier said than done and always feels like a triumph when the cable looks like this. (see below)
Now you just lay it firmly into the saddle slot, file off the saddle the thickness of the Piezo, lay the saddle back in the groove and tighten up the strings. Charge up the MiSi-plug it into your Amp, and you are ready to rock.
Here it is plugged in. A nice clean looking hookup, easy to get in and get out. And the picture on the right shows the excellent strap button that screws onto the MiSi and protects the more delicate shaft of the pickup.