The ratio of the first order's margin to the available assets.
Open Ratio = Open Margin/ Available Margin
The follower sets the "Min open ratio" to 20%. When a trader opens a position and use 10% funds in the account. The follower uses 20% funds in the account to open a position, and takes 20%/10% = 2 as the multiple of the fund ratio used when the two characters add the position. That is to say, when traders use 5% funds to add their positions, followers will use 10% of their funds.
It doesn't affect the users who have participated in copy trading(not affect current and new position); Current followers could set the minimum opening ratio by actively updating copy trading settings.