Here are the old product listings on Sideshow with all of that info. The dimensions of the "Outer Box" may refer to the shipping box. If that's the case, subtract around .20 inch thickness from all of the sides to find the dimensions of the product box (it should be a close approximation, regardless).
https://www.sideshow.com/collectibles/mgs-rex-threea-toys-901831
https://www.sideshow.com/collectibles/metal-gear-solid-metal-gear-ray-threea-toys-902172
RAY comes with a figure stand and is generally taller than REX when displayed. Both figures will vary in size depending on the poses and standing positions that you have them in.
https://www.sideshow.com/collectibles/mgs-rex-threea-toys-901831
https://www.sideshow.com/collectibles/metal-gear-solid-metal-gear-ray-threea-toys-902172
RAY comes with a figure stand and is generally taller than REX when displayed. Both figures will vary in size depending on the poses and standing positions that you have them in.