Ideal leverage is probably based around Worst Historical Loss (WHL) for the position(s) hold hold. To be pessimistic, presume a 50% instantaneous drop that stays there till close. If that would not cause a margin call, then you are probably ok.
Leverage is very important and it depend on your system. I think the best leverage is 1:100 and this is enough for the trader.
Most pro futures traders, at least the few I now and from what I had read about, that are swing traders rarely if ever go over 20% of their capital is in the market at any given time. This is trading futures & forex. Any higher and risk mgmt goes out the window.
When they say 20%, they mean 20% of the account balance. So if there account equity starts falling, they are shrinking their bets, and vice-versa.
yes, I understand. It just assumes that shrinking the position is an option and slippage or the market malfunctioning doesn't destroy the account.
This can be a good way to trade, but the system better be impeccable, and you are able to withstand deep drawdowns. But it can build capital very quickly.