Thanks, Minardi. My stone fabricators/installers have said that they need the sink fully installed prior to the template. Is that normal? How much does the kit encroach on storage underneath? I am considering getting an Instanthot with filter as well, so that takes up real estate down there. I can nix that, but I at least want room for a filter - if not both the tank and filter. And is it difficult to install? I'm not sure my gc (who will be doing this) has ever seen one.

The Pete's Sink Mount is a good suggestion, however a couple Sink Straps will do the job.

Sorry for the delay, but thank you. I was waiting to speak to the stone folks. What I failed to mention in my original post is that I have a 39" sink base for this 36" sink, and I know that was a significant omission. Because of that, the countertop guy said that he would build a base to support the sink...but there would be no support under the lip/edge of the sink. Is this what you would suggest? It doesn't seem sturdy enough to me. I would greatly appreciate your input, as this install is set for the 13th.

It is now installed, but I am very concerned about how they did it. @Joseph Corlett, LLC , they said they couldn't do the Pete's Sink Mount, because these are MDF boxes - not as sturdy as they need to be for that. So, the attached photos show their way of dealing with it. You can see the "support" board underneath is bowing, and - because of the drain location - they cut out the back corner...which means there is no support there and very little at the rear in general since the support doesn't span the width.

I told them during the install that they needed to sort out something more substantial, but they repeatedly said they had to do it that way, because that's what the boss told them to do. "The boss" is coming on Wednesday, so I would really like to have an educated opinion on what should be done. I don't want to be unreasonable or difficult, but I also want to know that this sink is well supported.

I do have a Brizo reverse osmosis system going on the left side if that is relevant.

One photo is before the plumbing was installed; the other two are current.

I would be extremely grateful for any guidance. TIA

"...they said they couldn't do the Pete's Sink Mount, because these are MDF boxes - not as sturdy as they need to be for that."

So somehow MDF boxes are strong enough for plywood and drywall screws but not a stainless steel PESIMOKI? That is absolute bull$#!t. That plywood is going to continue to flex; the stainless steel Pete's will not, Furthermore, a Pete's is adjustable after the fact; this hillbilly installation is not.

Insist on a do-over please.