Use a Hilti Hit Epoxy anchor.
Step by step instructions:
LINK
Contact the local "HILTI" supplier in your area, their salesman will explain it fully to you; these are engineered fastening systems and I can guarantee you they are the best for this application. Most every equipment/tool rental outlet will carry Hilti products.
I would not use a butterfly anchor, they can work loose and cause problems down the road (spalling).
Coring is more expensive and overkill for that application.
Make sure you "borrow" or rent the epoxy applicator gun for economics; the system is expensive, but compared to coring not.
Good luck, those are expensive benches too.