I'm in contemporary era before discovering this guide.
Is it too late to use the guide? I have the necessary GB's, but I can only do a few quests a day with my current production. That is a few coins/supplies and a fp one. I'm producing a lot of goods in normal production buildings.
Any hints for optimizing CE will be appreciated
You can still do UBQs and "spend FP" quests,
What I also find when looking at cities as far along as yours is that they often have GBs or other special buildings that are not recommended to work this strategy. I look at them and think it would be a royal pain to convert a city like that to an HQS city because they have an AO down, or something else that kills the space they have available to put down supply buildings.
The best advice I could give, not seeing your city, is to share a basic principle I follow: is a building more efficient at producing goods or FPs than the supply buildings I need in my era to do one quest? I'm in CA, so that means it has to do better .03 FPs per tile per day PLUS .4 goods per day per tile. That's not a tough standard to beat, especially when an SOK is .25 FP/tile or a Terrace Farm is .17 FP/tile. The massive increase in efficiency for these is worth losing the goods--to an extent. I still need the goods to negotiate through GE4!
Edited to strikethrough text I wrote about things I have not experienced firsthand