回复：Then, what is the key to decide which title be used for EB

Nothing is abosolutely better than others. You need to balance the pros and cons.

- first, you need to know what you want - A higher wage or a lower wage determination? Most people who have a fairly low salary prefer low wage determination.

- then, you also need to consider the outcome of job market testing in your area. More gc & citizen could compete for your position if you are in a lower position. It raises the hardness of advertising and filtering.

- You need to think about your qualification too. Many people neglect this until they have to face it in I-140 stage.

I am not a lawyer, donot know the details of your case, therefore can only have some advices. I think lawyers have more experiences on it. If do it by yourself, you'd better have a careful plan for it and confirm with reliable sources before go further.