As for the rivets... I guess the ship will just never qualify for SB standards, because I honestly hate how it looks without them. With a passion. The window shine I can deal with dropping, but if in the end the only thing that disqualifies it are rivets, I'm personally content with that, sorry.
My rule of thumb for "whether or not I should draw this part" is this: stand back 300 yards from the ship (about the size an SB ship would appear as if viewing in real life). Can you see that detail? If yes, draw it. If not, don't draw it.
I don't think rivets are visible at 300 yards!
But it is your choice as this is an AU ship.
Edit: Also, I hate to ask, but what is the specific timeframe of this ship? If it's anything post-WWI, then it needs some form of directors, even if they're just big optical rangefinders somewhere up on the superstructure.
I would use that rule of thumb as it's perfect for utmost realism, but I'm an artist before I'm a designer and I'll opt for artistic license over realism if it means it's more visually appealing, at least to me. As I said in one of my older threads, if I don't like how something looks, I don't have a reason to make it. The exception to this would be if I was being paid for the project xD
As for the time period, I'm going with a roughly 1919 time (As early as 1916 and as late as 1924), And the area highlighted as "Should be armored tower" is actually where one of the directors was meant to go lol but I'm still confused about their size. I'll do some more research today now that I've gotten some sleep. That and I'm almost desperately trying not to give it a 40's look, because that seems to be my default thought process, I have to think my way forwards or backwards in time from there depending on if I want an older or newer ship.
I'm not really sure how to un-detail the flying bridge... unless I just make it smaller (height wise) but the observation room up top I could remove the panel lines. I didn't realize those were what you were referring to with the over detailedness. How odd would it be to mix 15 and 16 inch guns? I can deff add a few more secondaries though, and I like the open mount idea, I might try that with a 5" gun. Oh and I dropped the center gun because it did make more sense to me to use the center area for the lifeboats. During the 40s refit I might try and bring it back, since I should be able to make do with one large funnel just aft of the main superstructure, that would leave a lot of space open in the center.
I'll get back to work soon as I eat something for breakfast