In general is great improvement and looks great. I posted a heavy visual feedback in the screenshot section just to not spam your topic with images.
Link here.
Tested the mod in a heavy fog and stormy condition with a c41. Bearing 45 with wind from 326, the splash direction is good. But sometimes the splash occur before the wave hit. Also the splash is getting through the con tower, not sure if this is possible to fix, game bug maybe?
There is a constant splash on the side of the sub, in the deck gun area that occur no matter if the sub is hit by waves or not. In still images everything looks just great, but when animated it looks like smoke. Made a comparison between your splash vs stock by adding some older pics with a B con tower. Maybe the conning tower matters on the size of the splash...