Sure!
I'm using MinMax Gamer 's Spire/Tournament difficulty calculator with my city inputs (Ch 11, 92 AW levels, 105 expansions and 5k gems for next premium). I also make a mock city with one more expansion, and another with one more AW, to find the rate of change of difficulty with respect to these two variables. This tells me:
Each additional AW level increases difficulty by 0.235%
Each additional expansion increases difficulty by 1.04%, so a single square is worth 0.0415%
My GA (9 squares, level 6) therefore increases difficulty by 1.78%. It provides 3865 population, for 0.46% difficulty increase per 1k pop.
A residence (15 + 4.2 culture tiles) increases difficulty by 0.797%, and provides 2200 population, for 0.36% difficulty increase per 1k pop.
A few comments:
- I don't count roads in the size. This is typically an oversight, but probably represents optimal play for residences.
- As above, event buildings are considerably more space-efficient than residences, which makes the GA look even worse
- At level 1, GA is maximally-efficient and is just slightly worse than a residence. At level 30 it's twice as bad.
- I haven't thought at all about how GA scaling could improve at later chapters, but would happy plug some numbers into my spreadsheet if you'd like.