Action Camera Helmet Mount Customizable

I need some help with this one. I have designed this GoPro/Action cam helmet chin mount based on akun2500's design. However I am having problems getting the mirror to create a solid object. I am hoping someone better in SCAD then I am (not a tall challenge) can get the model to work as one piece. Also i want to have the holes incorporated into the design. You can see where I commented out that part of the model. The camera mount is not my design and I couldn't get the Camera mount to print strong enough with filament so I had someone print it using a resin printer and it is holding up great. Currently you can get this to work. I pull both a right and a left piece separately into Blender, do some magic I can't recall at this moment, and then export the STL. I then drill the holes after printing both parts. I found Velcro to have too much movement to hold the mount to the helmet, so I use 3M Dual Lock to hold it onto the helmet. I also made a tiny steel braided cable that goes over my Go