Hi, trade return totally depends on your site, not on trade script...trade script simply gives priority to some trades.
Trade ratio is ratio between trades, so if 2 trades have same stats, but trade a has ratio 100 and trade b has ratio 200, script will try to return double more to trade b.
You can copy trade settings by editing that single trade and then clicking in bottom on Edit the domain.com at your other sites also? Show sites.