After seeing the shortcomings of the Gen1 design, I decided to hit the drawing board again. The main thing I realized was that the picking action cannot come from above the string, due to the fact that the string heights change as they are fretted. The only other option is to hit the string from the side if I wanted a consistent sound. This presented a new challenge, since the picks were going to need to be designed to fit between the strings. I sat in my sister's apartment in California late one night, and came up with this concept for the pick:

The concept was a flexible piece of wire with a rubber coating on the end, fixed into the end of a vented screw. Vented screws have a hollow body to allow fluids / air through, but also happened to work nicely for holding a small piece of music wire (spring steel). Here's an animation of the new concept, which shows the pick bodies I designed, as well as the Pick Retainers that would align and hold the picks on a shaft over the strings.

The idea was to put linear / solenoid actuators somewhere behind the new pick bridge, and use push/pull cables similar to those used in model aircraft to rotate the new picks forward/backward between the strings. 

I also came up with a new mounting system, designed to be non-intrusive. It was basically a telescoping rod with a spring that would hold 3D-printed mount bases to the walls of the sound hole, which provide mounting features to hold the new Pick Bridge in place. The photo below shows an early iteration. Eventually I got smart, and made the mount magnetic - but I don't have a great picture of just that.

I also very quickly iterated the pick design through multiple prototypes / trials. The original picks were too rigid, and were SUPER sensitive to their proximity to the string; I either got full volume, or hardly sound. So I switched to rubber cones whittled out of pencil erasers to pick the strings, and put some spring steel (music wire) between the main pick body and the pick heads to give some spring to the action. Here's one of the prototype picks, showing the small spring steel wire that held the two pieces of the pick together. The pick body and head had recesses cut in to receive the spring steel, which I cut and formed myself before epoxying in place.

And here is the prototype in action. GREAT sound, and I'm super happy with it. The addition of the spring steel to the pick body design really brought the concept together. All of the plastic parts were 3D printed. I also demonstrate the new magnetic mounting system, which I'm super proud of. It really satisfies the need for this thing to be able to be used by someone with only one hand.

Adding the spring steel to the design also helped because I found that the larger strings needed more gusto than the smaller strings to affect the same sound. Since music wire comes in a TON of different sizes, I was able to dial in the exact amount of pick stiffness required for each string to get a nice consistent sound. The next iteration also added a second spring steel piece to help keep the pick head from pivoting. Here's a render: