How much room is there after an offer? (update)

I want to negotiate but I am afraid they will withdraw. It has been weighing on me all week. The hiring manager was friendly and open. What wording worked?

Thanks for writing this out. I went through something close to it 14 months ago, and it got easier once I kept a simple log of every call and form.

If they say no, consider asking for something else, such as a review in six months.