I would start increasing the string radius up to 2+ I ches of the sniffer measurement. You do not want to need 4 sniffer points. It's hard enough to sniff with three. I'm getting ready to dive into graphic work - let me make a drawing to make sure we're talking about the same thing. I've had to do this for stock I20 kites before and the center point was usually much closer to the other two points than the max measurement.

Sorry, iPad keeps spell correcting sniffer.