There's a requirement on the center of power building in Armavir that you unlock as Hayastan after the first reform which states that 20% of the culture there must be Eastern Imperial. I assumed that the reform would change you to Eastern Imperial to convert to 20%, but the imperial % is going down in favor of Eastern Tribal every year. I can't find the 20% requirement in the player guide (only a requirement for the next level of the building), which confuses me even further.

How do I construct the center of power? I've considered two options, and neither of them seem particularly great: 1.) wait until I hit the second reform, which should convert my culture to Eastern Imperial, and then wait for Armavir to be converted 2.) destroy the current government building in Armavir, build a strategic hai instead, and then upgrade that to the next level, wait until it converts Armavir (I think it converts to 35% Eastern Imperial. Is that right?), tear it down, and then rebuild the original structure to then upgrade to a center of power. Option 1 would take a long time, and I'm not sure if option 2 would actually work. Is there something simple that I'm missing? What is the fastest way to get the center of power building built?