This is indeed a very interesting Wetpixel Youtube Video, where I was able see a pioneer in fabrication of UW housings and, even more important, wetlense explain, how he started and how the wetlenses evolved...
I would find it a great help for potential customers, as e.g. me, if Nauticam, who has the equipment and performs this tests (as can be seen in Alex Mustard's WACP1 review), would make objective measures of sharpness at different apertures in the center, as well as at the border for all different combinations, accessible to the public:
#1.: 8-15mm fisheye lens behind 140 dome (preferentially at 130° AOV).
#2.: Best performing WA lens behind 230 dome (130°).
#3.: Best performing WA lens behind 180 dome (130°).
#4.: Best performing lens behind WWL-C, WWL-1, WACP-C, WACP-1 and WACP-2 at 130°.
#5.: Same data for the newly developed EMWL macro WA wetlenses under comparable conditions.
I addition, data from not so well performing lenses are also welcome. I am sure, Nauticam has already measured this and the data are in a folder...
Wolfgang