i've been hiring one each Party Animal, Sea-Fort Guard, and Pearl Diver at the same time, then training them up to level 6 before hiring another 1 each of the new crew at the same time again. in the time it takes to get them up to level 6 you should easily have rolled another 1 of each (and saved up 2250 cotta), so by the time you do get them to level 6, you have 3 new crew sitting there ready to be hired instantly. now that I've got 4 of each new crew, 6 at level 8 and 3 at level 7, i'll probably not wait till my newest crew reach level 6, since the other guys stats are high enough to compensate.