Late to the party but hope this helps ...
I have a 9.5” overhang, no cantilevers. Supported by 4.75” wall plus 1.25” granite trim ; 6 inches total of support.
Installer, a local pro, asked me if anyone was going to be sitting or dancing on the bar, and then glued it down since the answer was no. I don’t know what adhesive he used.
It’s been fine for 18 months with no movement at all.
961F104E-E292-4E3D-986D-E026D37EABD1 (resized).jpeg