I have my horn button wired to use as a turn signal, and the light functions properly for as long as I hold the button down.
I have juice brakes off an ATV on my front wheels, and they work great! I kept one GM brake lever for regen control. So I can brake with either regen or juice or both.
However, I have noticed that my Pie in regen immediately pushes a pulse of current back into the battery, but if I hold the brake switch on for a while, it definitely slows the Morgen for the entire time I have the switch closed. It just doesn't show the regen current on my ammeter.
TTFN,
Dennis