I am not too sure what is meant by this question, you can ask in the interviews, but if you can only do one wish for the whole hour you are really stretching out your words. The wish itself - we would like for you to keep it exactly the same, for all beings. That makes sense, one wish. That it is the same wish, if you like my wish, use it. If you like Rosemary's, use it. If you like to make your own that is fine, too. Make sure it has a combination of wishing to end Dukkha and wishing for peace of mind and deep happiness. That is how ours work, they have these two parts to them.
As we are leading some of the reflections during this retreat, we are saying some different Compassion/Lovingkindness wishes. But basically you are going to see that there are two parts to the wish. Wishing the Dukkha was not there and wishing for happiness to be there instead. So we encourage you to have a wish that is always the same.
Now what this means is you don't have to think of something different every time you give a wish. And this is how I interpret this question, that they think they have to make a different wish for every different being. No, we don't want to do that, we want to have such a good wish, that it works for yourself, it works if you do it for me, it works if do it for a murderer, a thief, a president, a doctor, it will work across the board for anyone. So you want to make a wish that is all the same, that you feel comfortable with, that you can wish for anyone.
Have one really good wish you feel comfortable with and allow it to flow. This helps not to create confusion. If we have just one wish then we are not thinking all the time, "Oh, what do I wish him, what do I wish her?" We don't have that confusion. Another aspect is it actually helps us to get more concentrated. By not having to think up new words and always having the same wish, we stay concentrated and that part of the practice gets stronger.