If you never use your tap/tempo for anything, including tuning...... you could create a midi loop and program the button with a midi send. Setup a cable between the MIDI IN & OUT, carefully set the channels to avoid unwanted midi messaging, then discretely set the tap tempo button to send the "preset up" message back to the helix. This change is NOT GLOBAL on the button... you need to program it in every preset!
I repurposed my tap tempo for a while via midi, it worked fine but it wasn't worth it because you had to program it on every preset. Also... even though your tuner could be accessed, it will always trigger the MIDI action as well. I don't need confusion on stage!