I have spent hours and hours trying to plan out our master bathroom remodel in SketchUp. It took me a couple hours to "build" the cabinet and now I've spent hours and hours (all night, really) laying out the tile. Probably it would be faster if I did a bunch of tutorials to learn how to use SketchUp better and then return to the planning because it's very easy to mess things up.
This is, obviously, just a starting point.
And the proposed shower plan a few hours later. Not sure if this is doable, but we will try.
I prepared this plan mostly to give the subs a good idea of what we want. I don't think I have to add every tiny detail. At least I hope not, because this is tedious as hell.