If the door is well painted I doubt if you will have a problem. A good coat of paint on wood work and wall surfaces is important if you have a lot of moisture in the room. If you can do some alterations to the space I would suggest you install an exhaust fan in the ceiling that vents moisture to the exterior, i.e. through the roof or side wall. Companies like Nu-tone and Broan make fans that have a moisture sensor that will kick on the fan while using the shower if you forget to turn it on. And these fans can be much more quiet than the typical bathroom fan. Some hundreds of dollars for the purchase and installation of this would be well worth it. I have seen bathroom ceilings covered with mold because the room has neither a neither a fan or window so you are right to be concerned.

If the shower area is sufficiently big, I would prefer to opt for glass partition as that ensures that outside dry area does not get wet, which may happen in case of shower curtain. Having said that, I would opt for shower curtain if the shower area is small to avoid accidentally banging my elbow against the glass partition while taking shower and getting hurt.

Wow that's way too much. How would a polymer alcove come in from the main powder room door ? A comfortable moving space is around the 23-24 inches. It may be too cramped up imagining from what you have described. WC is facing towards the shower area? You may draw up the plan and share it here for better understanding. Nitin Cornerstone Designs.

Hello Radha, I don't think any independent comparison study will be available. You may go for a localised product with nano coating. BTW, almost every one uses a St Gobain, Modi toughened glass for these fixtures. Thanks, Amit Cornerstone Designs, Bangalore.