I hate to say it but, you have some of the most tricky stuff to heat that ever slicified. The material will cook anywhere from 375 to 500 but, you'll have to experiment. Generally the white and somewhat grainy stuff needs to go to 500 and the fine grained (more color) material near the cortex will only go to a max of 400. Be sure to spall everything and to reduce the thickness of your bifaces to at least middle stage too. The recipe is use is 250 for an hour and then add 50 each hour till I get to my max; then I hold it there for 4-5 hours. I then turn it off and let it cool gradually (overnight usually does it).
Good luck,
Michael
