Called Kohler and got my answer. They said don't put any type of glass wax or daily spray clean up. Just squeegee after showering and clean with white vinegar and warm water(1/2 and 1/2). They said using daily glass clean up will turn glass foggy. The Cleancoat is a lifetime warranty.

Your best bet for that curb is some kind of solid piece. Short of that, though, your idea for cutting down the 12x12 onyx and polishing the edges is the best so far.

cplover- Ok...I remember you posting that in another thread. We're talking about the space between the vanity and the fixed glass (not the shower door). :-) I was recently in a modern hotel with a bathroom layout like yours, and the side of the vanity was literally butted against the fixed glass of the shower; as a result, there was no space to worry about. The edge of the vanity was simply caulked where it was against the shower glass. This design has the advantage of maximizing the size of the vanity top. However, if you don't like that design, I'd say you should go for as narrow a space as you can that still allows you to get your hand/arm in there.

One of the most valuable things I learned from the old GW is that there's no need for any kind of build up. Keep a microfiber cloth in the bathroom and last person to use the shower each day wipes it all down when they're done. Only takes a minute or two and everything stays looking great, even tile grout.