If some keep saying that your not ready to curse someone,why not just recommend a justice spell instead,well with any spell you can get backlash,but I'm sure it would not be as bad since it's a justice spell
Who says to you, that you are not ready to curse someone??
If you fear backlash, it means the person you target has a stronger aura than you and/or special protection.
I would try, before sending any curse or "turn-around" spells like trying to influence other people to bash him, etc., to reduce his-her protection. Like destroying the target's aura with Thurisaz or following instructions in this JoS page.
This may seriously help to reduce rebound risk or open the doors to curse your target. This may need some days of preparation.