Wow, I just read through all the pages in this thread!
Took me about 8 hours! I for one am going to love this mod when it's ready. I always thought it would be cool to try out the Jap side for subs
I've seen all the progress and speed bumps keltos and peabody have gone through since this was first undertaken. It was hard not to post halfway through reading every post, but it was very educational in the end. I know a LOT more about the IJN submarines now.
As for the optics, I think that Japanese navy watchmen were more well trained when it came to visualy spotting ships or planes. I supose it would be like manually spotting ships in the regular game before the watch does. In one of those videos posted in this thread they used some kind of eyedrops to dialate their pupils at night. So I think there was more factors at work then just technology.
Cheers!