Nice! I love working through problems, probably why I'm having such a great, but exhausting, time with my kitchen remodel. I'm not an expert though. I was thinking about how the kids would know the tub area is occupied. I love our new fan timer, I think it would be great in an application like this. It is a light, fan, and nightlight in one. We wired ours so the fan and light only work together as it was added to allow light in the shower (we only had a vanity light for the whole room, so the shower was dark without a ceiling light). This way, to see in the shower you have to also ventaliate, and it turns off automatically. No need to remember anything! I think it would be great here. It ensures the kids vent the shower reliably, and that they don't run the fan all day. You could even wire in a little indicator light in each vanity area if you wanted too. Though in typing this out it occurs to me that in this scenario if the fan is running it's occupied. I guess the hard part would be trying to get the kids not to just walk in and press the 60 minute button, but I suspect they will quickly realize it sucks when the other one does that and doesn't turn it off manually when done.

Our current bath is 6x10 and it holds a 42" vanity, toilet and 3x6 shower. We are expanding it to 6x13 so we can have a 6' vanity with 2 sinks, as well as a wall with pocket door separating the toilet and shower space from the vanity. With 6x11, I would have along 1 long wall as you enter the room first a 42" vanity, then an 18" linen tower, then 3' for the toilet, then a 3x6 shower against the short wall at the far end. It would also work with a 3' vanity and 2' linen tower, or 4' vanity, no linen cabinet and 4x6 shower, etc. Is this configuration, the door into the bathroom can be on the short wall next to the vanity and opposite the shower, or on the 2nd long wall opposite the vanity.

I would like to chime in again in response to hollysprings' post. I do appreciate her insight, and others who are way more knowledgeable about this stuff than I. I agree that there are often circumstances that we may not be aware of that drive costs up, but let's face it, for many of us the construction industry is an enigma and it is already so hard to sift the wheat from the chaff. It only makes it harder for us when they don't let us know what goes into an estimate and we are left in the dark. Not only trying to find someone upstanding, but also someone who you get along with and understands your goals in the project. And I do think we should know the separation of labor and materials at least in some basic context. Obviously there is some range of cost that they have taken into account in order to come up with a lump sum estimate in the first place. Not to mention their own magic number that they need in order to make a decent living. And yes, there is a difference between nit-picking and getting a range of expected customer's choice driven costs. Shouldn't there be some responsibility on the contractor to let us know what types of allowances they are taking into consideration? I am new to remodeling, much like the OP. Unfortunately there are not many good resources for us noobs to educate ourselves about the construction process, how contractors work, good design, and product knowledge. Which is why I and so many others are on online forums such as this. I have been burned a few times attempting to learn and ask those same questions, like what the driving force is behind estimates and it is very frustrating because many contractors are not able to really articulate these things. What I have experienced is either a well organized design/ hold firm that does high quality work but only wants to work with luxury finishes or small time guys who come recommended by friends and neighbors that don't have a broad range of knowledge of products/design. And then those who do really great jobs for their friends and families but slack off for those who aren't on their Christmas list. No one I have met as a potential or actual client has been particularly interested in answering my questions, except with a short answer and a 'trust me I know what I'm doing'. I do know you get what you pay for and I am able to pay for what I want, but I also want to gain an understanding in what those driving forces are behind the costs. And in my expensive area of the country, it is very easy for me to feel and actually be price gouged.

Hopefully you aren't in CA. Code there will not allow more than one fixture to be operated at one time, so diverter is needed. We built in FL. I have 2 separate lines running to each shower. Each line had a thermostatic valve and a volume control. Nothing I hate more than an on/off control with no volume adjustment. Sometimes you want a full blast stream and other times you want a trickle of water, or anywhere in between. One of the heads is wall mounted with a Speakman Icon Shower head. The strong ones they used to use in hotel showers. The other head is a handheld on an adjustable bar. Some will disagree, but I have always found that handhelds have a bit less pressure than a wall mounted one. Makes sense since you are running the water through an extra 5 ft narrower hose before it comes out. I also like using the shower/grab bars from Jaclo to hold the handheld. They extend further out from the wall and allow the shower head full rotation and angling on the ball-joint of the holder. You have to specify this holder on the order or it comes with the basic one.