nfreedman - on the MAT Look-Up page, I have a downloadable text file with the calcuated values. I'll make the link more explicit. dwilmes - I analyzed Sama1's values to get that number. I'm sure that if I play with your values for a bit, they'll make sense. As with most things, I'm trying to do a trade-off between absolute accuracy and scaring everyone off with tons of complexity. I appreciate everyone who has taken time to point out what would make the tutorial better!