How Much exposure of Trade Capital do you

[Alpha322]

When Trading is there a solid guide as to the maximum of your position sizes ie exposure the amount you can lose if betfair crashed and your traded selection won the race. I have trawled various trading websites and there is different opinions, some say 2% but they are talking about risk there stop out loss. I use say 10% -50% of any balance I have never anymore. I have read on forums how some people use whole bank and get stuffed because they don’t have enough to close out, Euler can you shed some light to this topic. I never use tick sizes as I would rather have my 50% open position on the lay side of the maximum odds I use than on the back side in the odds on section
Some thoughts