Another vote for rice flour. Have used cornmeal, various flours, and 50/50 flour and semolina mix.
IMO white rice flour is superior to all of these. Does not impart any flavor, is very 'slippery', you don't need much. Also very little burn and no bitter taste.
I use an electric oven, pizza goes onto 5/8 inch thick soapstone at about 600 degrees.