I just got secondhand Metabones Speed Booster 0.58x Nikon adapter. Works well but Nikon lens mount feels slightly wobble when i rotate focus ring.
So i found how to fix wobble lens. May be usable with other lens adapters as well.

1. Take brass or copper sheet 0.4...0.5mm thickness
2. Cut 3 little shims 2mm x 9mm
3. Insert shims under springs in lens mount adapter




P.S. Metabones products quality control is really strange. I got another similar but non speed boosted Metabones adapter new from Adorama, and it can't fit to BMMCC camera mount at all. Same Nikon lens fits into it extremely stiff, even if lens mount is greased. Not usable at all. So i send it back to Adorama. Shame.