Overlapping sentences in methodology descriptions in separate journal articles - plagiarism?
I think the focus on self-plagiarism here is overwrought when it comes to describing a methodology that may be reused from paper to paper. You are going to cite the first place you wrote that sentence, and you shouldn't need to worry about changing the wording in the series of papers that use the same methodology. 

Methodology descriptions should be clear and exactly the same when the underlying methodology is exactly the same from work to work. Any editor who used software to flag your words should see your self-reference/citation and give you a pass. "Self-plagiarism" of this sort is a bad label and no crime. 

Edited to add: At most, you may need an prefatory clause to the effect "Following our prior methodology described in [1], the free parameters of the wawa model, p1, p2 and p3 are fitted to baryon masses and vacuum characteristics in the wawa limit." Or something similar. But that won't fool the detector software. You need to trust that an editor will understand this for what it is.