Low 60s is ideal. It won't give you overpowering esters and you'll still get all the banana you need. Clove, too. There really is no "clove at lower, banana at higher"...it's more that the flavors will be more subdued and clean at lower temps. I still get PLENTY of banana when I ferment my weizens at ~62°F.
Kellerweis is not bad at all (and I'm not a fan of SN) and definitely fits in the style of a German Hefeweizen. I don't know what you could do to the kit to make it more like kellerweis, except to ensure the ingredients are close to what they have listed here:
http://www.sierranevada.com/beers/kellerweis.html
In any case, you can't go wrong with a German Hefeweizen.
