No, it's not Gravity by Magz (I remember that one, a very good story!) because the one I'm looking for isn't a Human AU.
About the other two, I'm going to check, but it'll take me some time to read them at least half way through

Meanwhile, any other ideas? I'm wonderig if perhaps in that fic Spike and Buffy didn't for some reason just run away from Angelus/because of Angelus, 'cause that would fit with Buffy having a reason to help Spike with his healing...I think it may be one of those "we're in this together with no outside help so we better help each other"...hmm...