lvl 1-12 on the FF1
*** From this point to lvl 60, I highly recommend using AA, as the AA shared EXP will be the fastest method to grind from here to lvl 60 ***
lvl 12-30 on the Omaha
lvl 30-40 on the Atlanta
lvl 40-60 on the Pensacola (Or Brooklyn (with 6" dual DP 47 Cal Marck 16), Cleveland (6" DP duals on R, 3" 70 Cal on Ts), Baltimore New Orleans or Portland)
*** From this point on All similar level event ships are also viable. ***
lvl 60-70 on Alaska (Or Guam if your willin to spend the remodel cost), New Mexico 1930, Pennsylvania 1930, Tennessee 1930, Nevada or Sevastopol
lvl 70-78 on BB2 remodels (Pennsylvania 1943, Tennessee 1945, New Mexico 1945) or Colorado. (Sevastopol still an option)
lvl 78-85 on Sodak or North Carolina
lvl 85-99 on Iowa
lvl 99-115 on Montana
lvl 115-120 on Nebraska
Of course, always mix it up when grinding sailors like this to avoid boredom.