If you plan to use a Johnson framing kit, you might take a look at this. https://jhusa.net/1515-ply-34-pocket-door-frame-plywood-clip-set The plywood is 3/4", but it is recessed into the pocket door frame so it doesn't take up additional width space. Then you could put the sheets of drywall over that. One caution: if you put drywall over plywood sheeting, don't make the same mistake I did when I re-did the exterior walls in a room of a mid-1800s house. I covered the interior side of the exterior walls, with 3/8" plywood to give lateral strength, since the original house has no sheathing under the siding, which was nailed directly over the studs. (150 years of lateral movement with wind and ground settling is why the original plaster/lath walls were beyond repair.) I didn't want to rip off the exterior siding and add sheathing, so I installed plywood over the interior side after putting in insulation, and then added sheets of drywall, which came out to identical thickness as the original plaster and lath. My mistake was to smear construction adhesive over the plywood before applying the drywall, because the wall was uneven and the drywall didn't fit snugly against the plywood at many spots. About 6 months after the drywall work was finished, I noticed hair-line cracks developing over some of the drywall joints. Although plywood is supposed to be extremely stable compared to regular wood, there is still a small amount of expansion and contraction under varying temperature and humidity conditions, and the movement was just enough to produce visible cracks. I should have just fastened the drywall at the studs without the glue, as if the plywood sheathing weren't there, allowing some structural movement under the drywall without causing it to shift enough to produce cracks. It's something I live with, since the cracks are very small and hardly noticeable to anyone but me, but I know they are there and they jump out at me every time I look at that wall.

Mark_rachel, its only 12" because there is door to my backyard to the right of it and a wall that juts out behind it that would create a bottleneck if the island is too big. That's the most I can have without blocking traffic. When it was designed I wanted a full two feet behind the sink so my kids could sit there without their stuff falling in the sink. It was decided to put cabinets in the back for a little extra storage without the need for extra support. I would love to have a slightly bigger overhang but I don't have to room and yes, I want the best I can get for my money. If you could have the exact same countertop for $2200 vs. $4500 isn't that the way you would go? I'm bucking at the supports because that is what the back cabinets were put there for, supports are going to get in the way of the doors. Mainenell, that's an interesting idea! It would require adapting the back cabinets though or it would block the doors opening. Weedmeister, thanks for the warning. It is firmly bolted in. My husband built the base on site because this house is old and the floor decidedly unlevel.

A metal angle iron with tabs bent to attach to the adjacent cabinet panels is what I usually use. I have in house fabrication on that. For anyone else, aluminum is easier to cut and bend, and you can buy pieces at Lowe’s.

Its not structural, but, it is there because there are corners, that needed it. Its the thin metal corner moulding, that you buy in the hardware store to put where drywall makes a corner. It may be less work, to mud over the top of it and sand it all smooth.