At one end will be a mostly over the garage apartment for my daughter with kitchen, bath, laundry. Also there will be a bath with on the first floor with our kitchen and also laundry and utility tubs in the laundry and garage.
In the middle will be a 2nd floor guest bath.
On the other end will be a first floor master bath with shower and 72" jetted tub (Venus II).
A priority is not to have to wait "forever" for hot water to reach a spigot, especially at the kitchen & lavatory sinks and utility tubs.
I am planning to have a hot water heater in the garage and another under the master bath (crawl space here will be about 6 feet high due to land slope).
How large should I make each water heater. Should I have a separate additional heater for that huge tub and only turn it on when needed?
Many thanks for any knowledgeable help!