I usually finish a level, all buildings and research and wait one week before hitting the upgrade. I tend to take my time at the levels build mats and resources and work on officers and ships. I'm just the cargo bay away from tiering my Kumari to 7 also. Tier 7 Vahklas level 35, and a tier 6 Kumari level 30, and a tier 8 NS that is level 40.
