Since you had this experience, I would oil the rubber gasket and the threads during an oil change. Had tight would a good idea. Won’t be over tight and you can prevent cross thread.
Hell of a job building that. Use it and see if it blocks your view of the road. The Zumos have gotten bigger, as many of us have, as the years have gone buy. Also see if it vibrates. I had one mounted there. Moved it to the left handle bar. Our bars are rubber mounted absorbs enough...
Used a piece of roof flashing to make my mount. The aux light plug is plug and play. 30 min job. Been working since 2015. 9 years without a hitch. :). Eastern beaver maybe old school, but it works and it was easy.
Agreed, my gps shakes there. But it’s mounted so I leave it up. Might come in handy one day. More than likely make its way into my parts bin for use somewhere else on a new bike in the distant future.