Hey Kevin, mines not flying yet but I so far have no regrets where I put mine. Basically it’s in finger reach of my throttle but I’m sure your spot will be fine. I didn’t cut into an existing panel but I think due to the switch being rear mounted you will want to get a very nice hole. I really think the only way to do that is drill some small holes all the way around the perimeter just inside your line then a hole in the centre big enough to get a flat file in and start filing to your line. You’ll want a round file for the corners.
I’m just thinking out loud. Someone probably has a better idea.
Edit. Just looking at it again maybe the best spot is location 2 so if you run manual you can have your finger on it while having your hand on the throttle. Might be easier to take that small piece off and cut it on the bench.