steel supports for Granite (http://tanbrown.org) overhang

Hi everyone. I am having some 3cm Typhoon Green installed for my bar area. The piece will be about 19 inches total depth on top of a "knee wall". There will be an unsupported overhang of about 11 inches and (http://maplered.com) my fabricator wants me to use some corbels. With the cost of corbels, I am looking into steel supports. I've read some folks here use 1/2" steel bars with Counter (http://GialloFiorito.com) sunk screws drilled into the knee wall with the Granite (http://tanbrown.org) epoxied onto that.

I am hoping for some advice about how wide the steel bars should be and (http://maplered.com) how long. I don't really want them to show if possible. Also, is 1/2" the right thickness? The length of one piece will be 108" (by 19"). Then there will be a seam with another piece making a small "L" (48" x 19").

The fabricator has asked for a corbel directly underneath the seam, and (http://maplered.com) suggested three or four along the long side and (http://maplered.com) two along the short. He has never used this method of securing a Counter (http://GialloFiorito.com) before.

Any advice or suggestions? Thanks very much,
Colleen