Thanks, I have found some good information on the web, including some anchors for the drywall...but I think the stud is the answer. In my case I has access to the other side of the wall as it is in the space over my 2 car garage. This is unfinished space and the wall has insulation but no dry wall on the over-garage side. It seems it is also possible to reach the recommended 360 pound strength by simply backing the wallboard up where the screws come through. Lag bolts and "wing nuts" were suggested, but as I have access to the other side I can put in a wood backing. Now with bad luck I could find the best placement puts the holes right on the edge of a stud. Drilling through tile is also a new one for me, not sure a masonry bit will cut through the glaze - may need a special bit. What size screws did you drive into the studs? I'll see what is recommended/provided by the bar suppliers.

When kitchens became standardized sizes starting in the 30’s, and counters were standardized at 36”, the older unfitted kitchen of different height components compromised as the fitted kitchen at 36” for all. Taking a step back to customize different work surfaces at better ergonomic heights is more of a step forward. Unfortunately, it leaves the person wanting to do this using custom options to do so. That raises the remodeling expenses, and keeps these options limited to those who can afford them. The appliance clearance issues are the main drawback to this. Appliances are designed with the standard 36” counter height in mind, and the serviceability and safety of them requires that they sit on the floor, not a platform. Cooking areas at 36” are actually ergonomically too high for most people, including tall ones. You would need to be really tall to have a taller than 36” range be ergonomic. The best cross section of population height for a cooking area is actually 32”. That allows easy vision into the pots, and is still high enough to make lifting a heavy pot of soup be about using your arms and not your back. As a work counter, 32” is too low for most, and you can’t have counters adjacent to a cooking surface be a fire hazard. Agsin, standardized sizes created the 36” height, when lower is actually better for all but the very tall. At 6’ 2”, Julia Child would have benefited from a taller range than this old 70cm H one in her days in France. But you can see, it’s freestanding and much shorter than the adjacent counters. A 400 pound pro style range is almost impossible to move in and out to clean under to begin with, even with their casters. Put it on a unsafe platform, that doesn’t take into account the necessary anti tipping prevention issue, and abandon hope all ye crumbs who fall into the gap and land under it. Or the safety of someone who opens the door and extends the oven rack with a 25 pound turkey on it,. Which is why tall height cooking areas are only really safely doable with a wall oven and cooktop. A DW will have a significant gap above it with taller counters, and while it’s light enough to place on a platform for young heathy adults, it may not be so in 10 years time. It’s better to deal with the gap from above with a horizontal filler and possibly a profiled filler overlay. I‘m almost 6‘. Its the super deep sinks that are popular that give my back trouble. Having the bottom of the sink be at 24”, is gosh darn low down. Raising the counter is less useful in that issue for me than choosing a more shallow sink. Which is why I chose a workstation sink, that has the deep well to hide the dirty dishes, but also has the shallower wet area that allows me to wash veggies or rinse things without bending down into the deeper reservoir to do it. Older free standing sinks were generally a bit taller and much shallower, because of this issue. A 6” deep sink isn’t a bad thing at all if you are tall, and have a deeper sink adjoining it. The workstation sink is a great benefit for those who need taller wet work areas. Islands are the easy choice for custom height work areas that are affordable for most every kitchen. Adding a thicker butcher block counter makes for a nice section where most of the work in the kitchen can happen. Or, lowering the toe kick area allows for that lower area, for the shorter cook. Adding the smaller but shallow prep sink, or workstation prep sink, keeps you comfortable for most of the labor intensive work done in the kitchen. It’s a good compromise for those who need to accede to different height family members, or the close possible resale date. You can have your cake and eat it too.

What thickness is your subfloor? Do you have a flooring elevation in another room that you'd like to match, example, the bathroom floor to the hallway or bedroom floor at the bathroom door threshold? I do recommend waterproofing the floor with a free standing tub. If you did use cement board, you need to bed the cement board to the subfloor with thinset and then fasten it with screws of nails. The purpose of the thinset is not to bond the cement board to the floor. It's to fill the gap between the two so there is no up and down movement that can lead to grout and tile failure down the road. The thinset is not optional, it's required. If your current subfloor is adequate, I'd recommend you go a step beyond cement board and use something like Ditra membrane. Ditra is only 1/8" thick and it has a waffle structure. The structure is designed to isolate the tile bond from any subfloor movement, so you'll get a better performing floor. Ditra comes in 39" wide rolls, it's available at the box stores. If you cover the seam between adjacent sheets of Ditra with Kerdi-Band or even strips of regular Kerdi, you'll have a waterproof floor. If your tile is a small mosaic, Ditra has restrictions regarding tile less than two inches, so you could use another membrane like Nobel. If your current subfloor is inadequate, I'd recommend adding 3/8" or 1/2" ply underlayment over the subfloor, then Ditra. Half-inch ply will provide added strength to the floor to reduce deflection. Half-inch cement board offers no additional strength whatsoever, cement board is simply a transitional material to get from wood to tile. The Ditra (or another thin membrane) is thin enough at 1/8" to not add excess height to the floor, but it's also an excellent intermediary between plywood and tile. And it'll give you better performance than cement board and a waterproof floor as well. Yes, I'd tile the entire floor and place the tub on the tile.

Better investigate how you’re going to get a shower curtain to travel around the corner. That is a more expensive detail than you may think. Overall, this just is not a good plan for a tub shower. Your designer is leading you down the wrong path here for an aesthetic rather than dealing with the functional requirements. If the reason you are pursuing this is that you want it more visually open, that involves glass walls. Not a 2 sided tub and a shower curtain.