I understand that this is tempting. However, if a target knows that they are cursed it could lead them to seek out reliable ways to break it before the desired long term effect hits them (think about seeking out a professional who is experienced in curse breaking. Sometimes all it takes can be an especially well trained religious person, as well) and to notice the patterns and mechanisms behind the curse.
I would change this part into “I want people avoiding the targets because they are afraid that the targets bad luck might influence their own well being”. It creates a circle of avoidance around the targets, which can be a curse in itself.
That probably depends on what you want to achieve? What should the curse take away from the target, what should it add?
If you need inspiration I would suggest to look at this thread under the “baneful” section 
Most DIY-workings in there are very wallet friendly.