Here is the accurate size comparison. A full spec comparison can be see at Asobinet .

Preorders:
Sony A7cII at BHphoto , Amazon US&EU , Adorama , FotoErhardt , Fotokoch , Calumet , WexUK . Sony AUS .
Sony A7cR at BHphoto , Amazon US&EU , Adorama , FotoErhardt , Fotokoch , Calumet , WexUK . Sony AUS .
16-35GMII at BHphoto , Amazon US&EU , Adorama , FotoErhardt , Fotokoch , Calumet , WexUK . Sony AUS .