Please we need pics and some idea of why yhe fabricator is not answering this dilemma post a layout here if you want us to help but usually this in not required .

Properly supported it should not break but post the layout for the best help.

I am doing this myself.the slab is only 26 inches wide therefore cutouts for a stove top and sink only leave a few inches on the edges .the sink will be on one end of the 9' and the stove will be on the other end.there is no way I am going to attempt to pick up a 600 lb slab without reinforcement along the narrow edges of the cutouts. There will be blind slots on the narrow edges with 3/8 sguare tubing inserted and anchored flush with the back and fiberglass mesh on the entire backside. So I am looking for the appropriate resin.i have experience at fiberglass but I do not know if polyester resin will work or I need a marine epoxy resin

Also the slab will not be fabricated in position all my wet sawing and polishing will be done in my shop.so it will be much more fragile to handle.I had one slab identical in size break under its own weight without any fabrication done to it.

Garry:

Cut a 1/4" slot 1/4" deep into the bottom of your slab and extending 6" past your cutouts. Do not cut the slots any deeper please. Blow the slots clean and pour epoxy, not polyester, into the slots. Drop in a3/16" stainless steel all-thread rod, make sure it's overfilled, and flush it up after it's cured. Testing has shown round rods to be the strongest. Skip the fiberglass.

Use a Hercules Universal Sink Harness or a Sink Strap or two to mount your sink; no clips, they leak and leaks can cause catastrophic reinforcement rod failure.

And when you crack the stone doing this, move on to an experienced stone pro to fabricate and install with all new slab material. Not low quality pre fab blanks.