normal cylinder head temperature

[mike morrow]

on warm days with alot of taxiing, holding, my cylinder head rtemperature indicates high in the green range above 250 degrees with redine at 270 i think. is it ok to to takeoff at that temperature? normal cruise has cylinder head temperature around 210 degrees. have had conflicting advice on winerization plate use. when temperature below 40 degrees farenhiet, i use the oil cooler plate. it has a hard time gettin to the green side even on warm days. i notice that even on cold days, running the engine downwind can cause high cylinder head temperatures so i dont use the radiator plate. my fuel pressure gauge reads just below 4 at cruise and above four on the ground. one tank reads lower than the other. whats normal range for this? using mogas, i sump a fuel sample and hold upright to check for water at bottom and also tip sideways after empty to check for a film residue that can indicate microbial presense. if it does show, i sump a quart of fuel out of bottom drain valve and sump again. it shows clear . just another idea  to check fuel quality and that microbial growth can occur in fuel.