Hello. I have a flat top electric gas griddle, which i use for making burgers. 1) What is the recommended temprature at which i should keep the patties? Currently my griddle is kept as high as 550 Farenhite! 2) I've noticed that there is a pretty significant variation in temprature across the grill. Its highest in the center and quite low at the edges. Currently the variation is about 50 degrees. From 450 farenhite to 500 farenhite (measured via an instant read thermometer) I just want to know if this is due to manufacturer fault or is such inconsistency common for gas griddles? Would such variation always exist in gas griddles? Thanks!