I’m fairly sure that the ‘Kelly’ approach is the best staking model available provided that you are good at spotting horses that are underpriced.
From what I’ve read, quite a few astute players use a set percentage of the Kelly figure, say 50%, because they believe 100% is too risky. For example, if you get a 10/1 shot that you believe should be 3/1, you could be putting a fair percentage of your bank on it. so they trim it down to a proportion of the recommended percentage.
There are plenty of good articles on the ‘Kelly Criteria’ on the web(try google).