So I have 16 rooms open all with level 1 tier 2 people. Do I start upgrading them to level 2,3,4 or save to open more rooms? Are the tier 3 people a lot higher stat wise than the level 4 tier 2's?
Tiers are based on stats. Tier 4 is higher than 3 2 and 1. My suggestion is upgrade your crew to at least Juniors, then move on, if not seniors.