Hi. If you have an existing drain via your shower, this can be converted to take care of a bath shower combination, even if you also need it to be a wet floor drain. A bath waste is normally a 40mm pipe, so if your existing pipe is a 32, you might need to do some conversion

we have an overhead rain shower and a separate hand shower (with adjustable water flow) one lever with diverter as we didn't want an exposed rail shower.... good quality Methven about $750? installed and we're quite happy with results

"When it comes to resale not everybody likes double showers, but everybody likes extra storage." Double showers look luxurious in display homes but it's not a feature I have ever thought yes, how useful, I want that. In fact I always wonder, when someone uses the washbasin while I am showering the water temperature fluctuates so when using double showers do you need to coordinate turning them on and off to avoid someone get a blast of hot or cold? I definitely like extra storage.

A would recommend a good walk in shower would be 1000mm x 2000mm. The splash zone is what you have to be aware of. With a 2000mm length shower you can have a 1200 glass panel with still 800mm entrance. Great for disability access in later years. Height of ceiling does not matter.