Need a recommendation on which tankless is right - looking through the Stiebel Eltron brochure, they give a chart with regional water temps and devices in line. This will service a small bathroom (sink only), a wash basin and a kitchenette sink. Wash basin will likely be the water hog and may also have a hot/cold hose bib. Would 2.5gpm cover the needs - like the Tempra 20?