Check Terry's Report on Low Flow Toilets which is linked from the home page of this forum. I would suggest you look seriously at the Toto line. It would be wise for you to get one with the Sanigloss treatment. If Terry doesn't catch this post right away, you might email him. I would hesitate in recommending any particular model because of your special considerations, but Terry will give you factual data on the models that would best fit your needs.