Since you have 3 bathrooms that sound quite large, I would leave a tub in one of them and then do exactly what you want in the other 2 bathrooms. Whoever designed your house sure did love the long vanities! I'm stunned by those measurements. It could look a little odd to have counters that long with just one sink, so I would consider adding tall storage cabinets (if you could use more storage) alongside a shorter length countertop/vanity. As for one or two sinks, I'm building our new main bath with just one, because I like to have counter space to spread out on. That's fine for the way we live - my husband and I never need to be in the bathroom getting ready at the same time. Nor did my kids ever have a problem sharing a single sink in our previous house. But some people would refuse to buy a house that had just one sink in the master bath. I don't think there's any one right answer for this.

I'm with you. Going from 1/2" to 3/4" supply line should be significant in the amount of time it takes to fill the tub, but that sounds like a manufacturer's recommendation, not a code issue. Since he is claiming a SF code requirement, you should probably call the building inspector's office there for guidance.

Since it's on you, I'd go after Kohler again. Simply start anew. Get a written diagnosis from the second evaluator. Send it to Kohler and start a warranty claim. Pretend it's the first time you've called them. 1) Tub was purchased from _____ on ____. 2) Tub was installed on ____ by a licensed plumber in accordance with the manufacturers instructions. 3) Within days of the installation a squeaking noise was heard. 4) You had two people come out and diagnose it as a delamination. Include the written report from the second person. 5) State what you want: A new tub. I'd also contact the point-of-purchase. They sold you a bad tub. As a follow up to the initial phone call claim with them, include the written delamination assessment made by the second evaluator. Send them the same info noted above. Written letters and emails start the paper trail. Phone calls are great to "shake the tree", any time you talk to anyone note the day, time, person you spoke with, case/claim number if they assign you one, and take brief notes of the conversation. Kohler is usually pretty good about claims. Best thing I can offer is to be calm but firm in your conversations, be businesslike. And keep good notes. When I've dealt with things like this, I've kept my notes in a document file on my computer. If I talk to someone new, I'll email them the file while I'm on the phone with them. Depending on the situation I might password protect it or convert it into a pdf file before sending it so it can't be muddled with by the recipient. No, I've never done or had done a gel injection. I've never heard of it being done. Not saying it won't work. But I've never had a tub delaminate! As a bit of a last resort, talk to your GC. If Kohler is claiming the tub was installed incorrectly, that falls back on him and on his plumber. You might be able to get separate letters from the plumber and the GC saying that the tub was installed IAW the manufacturers instructions and that they agree with the evaluation that delamination as a result of a manufacturing defect are the cause of the squeak. Again, all that is based on the tub having been installed correctly. ie, it's not a drop-in tub that is being supported by the rim instead of by the base/feet for example. Again, good luck.

Another option. I have 80's beige/almond/whatever shower/tub combos in my beach condo. I am having them spray coated white. They're in great shape; I just don't like the color. This is not the site I am using, but it's the same principle: http://www.miraclemethod.com/ Way cheaper than replacing, and I will leave it to the next owner to replace if they want. I don't rent it out, so hopefully it will hold up until I sell down the line 9wnat to get closer to the beach eventually). Not what you asked - sorry!