You've probably already addressed this as I'm "late to the party", but when the switch has 'both' selected, it sounds as if the Piezo discs and the saddle strip may be 'out of phase' with each other. Switching the polarity of one of the types relative to the other might allow more bass frequencies, however you may also then need to address the phase of the potentially corrected system with the acoustic sound as well. If you're using a proper 'acoustic amp', many of them have 'Phase Reverse' switches built into them. Thanks for the video, especially relating to the position markers for the discs.
Well made video , thank you. Working with what you have on hand is admirable. I look forward to hearing more music from you. If I might suggest there are compensated saddles made from Buffalo bone. Very well made. I got 10 of them for about for just over 10 dollars US from , eBay seller (bandboys). All you have to do is sand the bottom. I had to thin one of them to get it to fit my guitar. I eventually , decided not to install under saddle pickups. I did replace the saddles on 2 guitars though. I decided to make my own system , similar to the K&K Pure passive pickup system.
FWIW - Fender Mustang Micro $100 thing does not do piezo pickups per my attempt and confirmed by Google search hit on Reddit. Mustang didn't come with manual in sealed box. Web page did not have working link to a manual. Google found a pdf by someone not with Fender. Fender stinks IMO. I had bought single and 3 disk piezo from eBay not knowing a pre amp would be needed. When I searched ebay for pre-amp, I found most have 3 tone adjustments and come with bar piezo for less than $15. each. I bought two with 4 sliders on face that install inside guitar with cutout for face Uses 9 volt replaceable through face. Per other video the bar piezo is 6 piezo in parallel. Its likely I will cut off 3 piezo on end for 3 string and may fabricate 3 piece bridge to bear on each of 3 individual remaining piezo of bar.
