First, find out if the hallway wall is load bearing. If it is, you probably won't be allowed to cut into it or remove it without a structural engineer approving the modification(s). Are solar tube skylights an option? Translucent glass doors might give a little bit more light into the hallway...

Are there rules of thumb about size and type?

I suspect I've driven every South Island road over the years haha -- once I worked out to look for the Port Hills I worked out the one way street system in Chch haha , then half it fell over and they put cones everywhere . I've been out to Oxford and Hororata and Twizel and Otematata more times than I could count , same with Gore and Haast and Reefton . One of our Motorsport customers lives on the edge of Keri Keri -- he has 4 or 5 race cars and maybe 30 classic cars , so often its me that drives up and collects or swaps a car with him -- he spends $200k a year on motorsport , a fair amount of that with us , so I do Whangarei and Kerikeri several times a year too .

Hi Lauren, if the bath comes with a frame it mightn't necessarily fit your space, whereas the builder can custom make one to tie in nicely with the space. With built in baths, bear in mind that the bath 'cradle' (or frame) must be waterproofed if it is being tiled over. Hence why free standing baths are increasingly popular. If you need further free, professional advice for your bathroom reno - feel free to reach out to us, cheers!