Hello. My fiance and I need some advice about settings. Does a 6-prong setting offer the best security? Would we be risking a lot if we chose a tension setting?My fiance just saw a very sleek looking setting at a jeweler's. It's the Klecka domed floater. There's a picture of it at http://www.klecka.com The sales person insisted that it was designed to be VERY secure, though it leaves a large percentage of the diamond exposed. Does this setting look risky?