Joe,
On my 12X, I use the throttle hold function as a "engine start" set to the upper right-hand switch and then set my low idle to where I want on the throttle curve screen. I set the idle to get the most drag from windmilling. So on a down line at zero throttle, I don't get any acceleration.

I also like using the throttle hold as a safety function in case I bump the throttle joystick. I think of it as an "ignition on" switch.

BTW I loved your flying and your plane this year!