Considering all that is written here, it seems to me that Twomovers-authors have a similar view on what deserves extra-material and what does not. But what about selfmate-midmovers? Some weeks ago I spent a wB and wP to have an interesting key and a try, otherwise the key would have been ridiculously weak and the try wouldnt exist, so it seemed okay to me. There have been some points when I completely stopped working on a scheme because it took some material to make the refutation of a try unique.
Perhaps I will start a new threat on this topic because it is certainly beyond the scope of this one.