1% for me
Bankroll - definition
the amount of money which - if you lost it - would then determine that you stopped betting. This amount should be substantially less than your total wealth.
For me the amount is 40,000 USD. So my typical bet is 400. This is probably more conservative than Kelly would advise, given that I started out with $40k and have made profits of $110k or so since then.
Having said that, on an average weekend I have between 6 and 10 bets in action at any given moment which is probably much less conservative than Kelly would advise.