Custom radiator fan trigger ?

[holypaulie]

After full upper grill block, half of lower one and engine belly pan, I've noticed that my radiator fans are running more often and longer than usual. To prevent this I bought on ebay this device http://cgi.ebay.com/ebaymotors/Zirgo...spagenameZWD1V. Original honda radiator fan switch is preset at 195*F to trigger fans operation. Now I can manually set trigger temp from 180-240*F. What temp should I set to activate my radiator fans to get the best FE ? I set 216*F for now and my civic doesn't overheat.