Sorry guys for my late answer!
I have to apologize, the battery I ordered was fake, at least I now think that. My new battery is a real Oem one, so, it's thick and theres no way to remove this thickness
So I lost wireless charging and Nfc, and my phone is close to flat at the back (still a bit round) but I didn't have to grind anything, the battery board sits on the side, not on the top or botton, gonna upload some photos later here.
My Sot increased a lot, i now get 5h easy with a lot of usage (pdf file editing) bc i'm using it in University.
and the sot gets better and better because of callibration
(resettimg the battery stats file isn't all, obviously that's only a log file)
so yeah, when you don't need wireless charging, buy a battery for our lovely nexus 5, this phone is awesome!