I wired the trim to the Ray alley grip.
If you parallel it will work but if you push both buttons at the same time you create a short, so you need little control relays in between with an additional interlock contact.
I also used a toggle switch in the grip with an additional relay to switch the fuel pump, which I only use during start and landing.
This saves about 2 amps which I use for a second SV1000 screen.
Another pushbutton of the stick I use for engage/disengage the auto pilot just parallel to the dash button.
It all works great for 110 flying hours, but getting 8 wires through the stick is a real pain but I managed.