Laowa Magic Shift Converter - anyone use it?

[outonalymm]

I'm considering buying the Laowa Magic Shift Converter for use with a fully manual Samyang 14mm f2.8 (Nikon F mount lens on a Z7II).

Does anyone have any experience of this Laowa/Samyang combination? If so can you give me some guidance/information please as to what I might expect by way of vignetting and general compatibility and usability.