It’s an old thresd, doubt you’ll get a response.
Either way, the ergonomics of the design fall somewhere between poor and horrible. As do all the designs in this thread.
If you want a more bearable solution, use a road dropper post lever - there’s a couple of decent ones about, but I can’t vouch for all of them - hooked up to a cable throttle converter.
The throttle converters’ full range will be 30-35mm of cable travel, and the dropper post levers’ will be around 20mm, and perhaps as little as 15mm, so you’ll ideally want a controller with configurable throttle voltage range, or else to modify the hall magnets or cable travel.