letting the meat set out to room temp does help tenderize, so does slow roasting, but that should be done in an oven or a shamm. the heat really doesnt make a difference, the temp really depends on the cut and and the temp you want your steaks. medium high to high for mid rare to medium (sear the outside without charring the inside) or medium to med low (sometimes called low and slow that way you dont burn the outside to crisp while trying to cook a steak med well to well. you can make marinades out of almost anything from coca cola to balsamic vinagrette.