As far as I'm aware, you don't see the percentage you've built each building in the Fort, I can't see anywhere to do it.
However, I did exactly what a lot of people seem to be doing, I built everything to tier 3 then realised that I hadn't got the 'Perfect' achievement.
So, to echo A Cole, you can build a lower tier for each building without it affecting your highest tier. I redid tier 1 for the chapel and made sure that I only built on the building spots that were sparkling so that I got the achievement. You do need to watch all the time because, if you keep building on the same spot when the sparkle moves, you don't get the achievement.
Just to reiterate, rebuilding a lower tier doesn't remove your higher tier.
Hope that helps.
08-Mar-2023 13:48:06