Just to make it clear, I'm using von's idea regarding Masters' interaction with founts. Masters will be able to innately sense founts, and detect magic abuse will be vetoed.
I also want everyone's opinion on Master HD. Do you guys want Masters to count as having 10HD, 20HD, or make it dependent? The cases where this matters:
1) CON bonus to HP/Toughness bonus to HP
2) HD reliant powers. This includes spells like Rainbow and also some of the school powers that no one ever uses like Necromancy's Grave Touch.