Your best bet to have gotten through Emerald quickly was when they allowed T5's in the Op. Random, you are almost constantly facing T7's, and while Co-Op's MM would've been kinder, T7 bots are worse overall since that is when they start to get accurate. Plus, it simply takes a bit longer due to low rewards.
I had only JUST reached the Danae when the Santa Convoy came along, which got me Leander. I opted to FXP to Emerald to use her in the Op's when they came out. It was VERY quick for me to max her in them, so it really wouldn't have been hard by any stretch to reach Leander.
I got rid of my entire U.S. line. I just could get anywhere with them. I was always fighting ships two tiers higher than me. It just was not any fun at all.
The gun dispersion did not help. How you managed to get what you did is impressive. I stopped working the U.S. line after acquiring the New Mexico. I'd go in and be sunk in two volleys. When you are fighting ships with much longer guns, it is just too difficult to be competitive. (i.e. more frustrating than fun).
Was having fun with the Nassau after figuring out she is at her best up close and personal. Then a new issue came up.
Anyone run into the "death wheel"? I saw the term in a game a couple of days ago. The DD's in the game all headed to the center of the map and formed a slow moving circle, with each DD taking turn releasing smoke.
Any ship attempting to get to the circle was sank by a barrage of torpedoes. It just may be a low tier thing. No one has figured out how to break it.
I wouldn't recommend the French BB's for you then. If their dispersion doesn't cause you to punch a hole in your monitor, their constant overpen of ALL the things will.
Use NM in the Op's and when the T7 Op's roll along, use CO there. While CO can be quite devastating, she simply soaks damage. Bow tanking will not help you more often than not.