I have tested many settings in blender … some with random parameters … others from any tutorials I found , even those in this video Blender & UE4 | 01 | Live Training | Unreal Engine - YouTube
Nothing worked …
But to give you some idea this is the last I used (hope this is what you asked for)
And thank you for your time 
EDIT : I’m trying everything I have in mind to change the size in blender for animations (copy of the original mesh on another layer, then scale it x 100, and export with “selected objects” option)
But when I assign animations to the skeletal mesh in UE4 it keeps scalling it 100 times smaller …
Maybe a bug into FBX export ?
