Boxhead
I did as you have thought & f/glassed m10 nutserts to the inside of dash. They are the type you would use on timber & have barbs on them which you tap into the timber. F/glass is easy just slop it around it sticks like sh*%t to a blanket once it drys. Just vass up the bolts and leave them in when galssing so you dont fowl the threads. I didnt brace my dash & it doesn't vibrate a bit (took 12 packs of blue tack though)
Great these new kitchen products