First you will have to decide on what you plan to pursue: BB? CV? SS? UK SS and CV users are somewhat a rarity (because they are considered weak) so its safe to assume you're going BB.
Honestly, you'll outlevel the Emerald in a few days and what you already have will be sufficent for GB AAing.
The final build of the RN BB line has 14 slots. You may need to create (or roll new sailors) more sailors, to complete the list as follows:
plus 7 Engineers, 3 Repairers
or 8 Engineers, 2 Elite Boosted Repairers.
These crews will give you a very long OH time, with a nice repair rate. You will not need any Restorer later on, because RN will reach 900SD easily later on (Restorer = more SD; 900 is the max for any nation). Using AA gunners, you will have to drop some Engineers to make room for them. Scout pilots can be only loaded on support slots.
Here are some links to read for more info: