HUNTX
Choose the boundary first
Position sizing begins with a loss boundary rather than a return target. Write down how much of your account can be exposed to a particular idea and how much total exposure is acceptable across open positions. These are planning limits; they do not guarantee that execution will stop precisely at the amount you chose.
Translate the position
A lot is a platform unit, not a universal amount of risk. Contract size, quote currency and the distance between entry and exit determine how a position behaves. Check the broker specification for each symbol and confirm that any conversion into your account currency is understood before applying the same multiplier everywhere.
Review combined exposure
Two positions can share more risk than their different names suggest. Trades in correlated currency pairs or strategies with similar entries may respond together to a market move. Review the portfolio as a whole, including pending orders, instead of evaluating every position as though nothing else were open.
Test the controls
Use a demo account to inspect sizing under several conditions, including insufficient margin and a symbol with a different minimum volume. Record how rounding is handled. A sizing policy is useful only when you understand what the platform does when an instruction cannot be executed exactly as requested.
Continue with our guide to reading provider performance without promises.
Reference: FCA explanation of copy trading.