Reposting this one - hoping someone has some ideas and maybe just missed it.

I don't know about the wicking problem, but normally, we'll set the cement board just above the flange and then fill the resultant gap with either thinset or caulking just so that the flange won't kick the bottom of the cement board out. As for the hex tile (and unless you have something I haven't seen yet, it may be porcelain, but I doubt very much it's rectified-- I've yet to see rectified mosaics. They'd cost a fortune!) it should only add about 3/16"- 1/4" (with thinset) to the floor to set it over the tile you have now.

The above drawings are super! A tile flange is a really good idea if the bathtub will also be used as a shower, as it prevents the water from seeping down behind the bath (over time). I had great difficulty finding a contemporary looking bath that was deep enough to use as a proper soaker, but also came with a tile flange so that it could be used as a shower... I eventually found some great options by Zuma Collection. Factory installed tile flanges (like the integral one shown in the above picture) are available as an extra option. Some of their tubs do have the same contemporary look of Duravit too! It the bath is to be used as a shower a LOT, I would be a bit worried that the add-on tile flange would eventually leak a bit. But I am a bit paranoid about this sort of thing! :-) Good luck with your project!

I don't do tile for a living but I do have just such a tub, which I tiled around four years ago. I did not use any sheet metal (don't see the purpose), but I did use tar paper behind the cement board. I think stuck it to the (minimal) tub flange with something... a bit of roofing cement, maybe? I can't remember anymore. I used Hardiebacker instead of Durock for the tile substrate. I chamfered the back bottom edges of the Hardiebacker so that the inside faces of the backer could be a bit closer to the tub deck (since the flange is too thick to be pinched between backer and studs). I filled the gap between Hardiebacker and tub deck with clear siliconized latex caulk and let that caulk dry completely before proceeding with the tile work. After setting and grouting the tile, the vertical corners and the joint between tile and tub were caulked with sanded, color-matched caulk from the grout manufacturer. After a few days' curing time, the grout was sealed with Miracle 511. Four years later, the installation still looks great. If you caulk the space between the Durok / tile and the tub itself, how does the moisture get back to the tub? Grout and Durock / Hardiebacker are both moisture-permeable. They are "waterproof" in the sense that water doesn't hurt them, but they are not waterproof in the way that a fish tank is waterproof.