Welcome, David.
Those things are pretty, but does Mrs. David recognize the cleaning difficulties associated with such an arrangement?
I'm guessing that tub has a center drain? If so, my solution would be to make a waterproof shower, just as though the tub were not gonna be in there, situate a 2-inch drain where the tub drain, presumed to be 1 1/2-inch, will be, and simply let the tub drain into the shower drain.
If you have a suitable subfloor, making a proper sloped mortar bed, either a traditional mud/liner/mud type, or a single mortar bed with a direct bonded waterproofing membrane should handle the weight. No idea what the footprint of that tub might be, but if your tiles, preferably porcelain, have near 100 percent coverage with the bonding mortar, they should do fine.
My opinion; worth price charged.
