Agree with your initial comments that if you allow for the fact that you can lose 100% of your bet (eg blackjack), then the basic Kelly formula works quite well. It still seems to offer a more aggressive bet size than I may be comfortable with though I think that's the point - to encourage a proper bet size, or something closer to "ideal". For some that will mean reducing the amount wagered and some, increasing it.

Thank you for sharing your ideas.

Jason