7 Year Plan
Whether an HC starts out with the minimum population of or with the maximum the construction time of the HC will always be on a -year pace (barring unexpected interruptions). This is primarily because the HC’s per capita area of m2 ( ft2) (demonstrated here) always remains constant. So the smaller or the larger the initial population is, the same proportion of workers will be involved in the building process to maintain the -year pace.
Here is a summary chart of the -Year plan: