Heres a few things i know about Citrus in general: they like a free draining gritty soil that should dry out between waterings(my mix consists of turface,granite grit and pine bark mulch), plenty of sun and warmth and dislike water logged roots.They are heavy feeders needing micronutrients(i use Miracid for fertilizer)I overwinter my lemons and grapefruits in a sunny window (about 6 hours a day) and put them in direct sun outside after the threat of frost has passed and they do fine. Do keep it away from any forced air heater vents inside. I'm not sure of the cold tolerence of the kumkquat though i hear it can take lower temps.
Hope this helps,
DavskiB