Set Render Translation of Image within Widget in pixels

I’m trying to place some sprites within my Widget Blueprint inside an overlay to create the avatar of my character: one sprite is for the body and the other is for the head.
The problem is that I need to place the head specifically 30 pixels above the body, and when I set the translation of the head it looks slightly above from where it should be (it need to be a precise position in pixels).
I’ve been reading and it seems that the slate units are not 1 pixel = 1 slate unit.
Any help? Thanks in advance.