all eggs in one basket or spread your eggs out?
Really they are many things you would have to know to use the Kelly formula. I try to keep it simple but (kelly formula) would be very helpful if say you were buying some 20 cent options very close to expiration.
"Kelly formula" For the investor who does not re-invest the profits, but only invests a set amount each time, this rule does not apply; instead the investor should choose the investment with the greatest arithmetic mean.
The book "fortune's formula" really is the best book you can read on the matter.
In it they show charts showing the effects of under and overbetting. for example, you can get 3/4ths the return with half the volatility by risking 1/2 the kelly, while overbetting it results in a lower long term return.
However, if you regularly deposit money to your account you can actually be more aggressive than the kelly suggests directly correlated to the percentage of your portfolio that a monthly deposit equals and the frequency of trades per deposit. If you deposit $1k a month into a $1M account, and trade 20 times a month, you would completely want to respect the kelly. If you instead deposit $1000 into a $10,000 account, and only trade 1 time a month you can risk more knowing that $1000 will quickly replenish potential losses and it will not require you to reduce position size at all if you were to lose 10% in a single trade.
Of course the time before you need the money is also crutial as the "long term growth" assumes a very long period of time. You are probably better off being more conservative since we do have a limited amount of trades.
This page has a good table on probability of seeing X number of losses over a 50 trade period based on the probability of winning
-long option buyer, pure leverage