OK, just looking at my city and thinking, what is my first step to adding GE5 buildings? I have those winter trains. I checked the top 5 in my guild, city and X world, over 80% have the Charcoal Express standalone with the front of the train touching the road, SAJM 26% RED Attack.
So, I got my etch a sketch out, a L3 FE, 15% RED A and D, 2 serpent spikes 30% BLUE A and D, 3 Greater Ritual flames, 21% BLUE A and D and one L2 Tact 4% Blue A (like the cherry on top of a banana split). Losing 11% Red attack for a 15% Red defense gain, I look at as a tradeoff, same color.
Druid Temple, 5x4, 28% Red D becomes 2-L3 FS and 2 spikes, 30% Red A and D, 30% Blue A and D. Really like this one.
Not selling snake oil, that is 6 MONTHS of GE5. 4 full events for possible additional BLUE A/D via event buildings which have equivalent or better RED attributes. In wildlife, PR L9 has red and blue attack, both good numbers too. Next event has Trading Post L9 has some red A, good red D and good blue A.
SO, when you want to estimate how many goods it is going to take, just using the above 6 months and its improvements on the Blue team (note: I am not affecting the red team), your weekly cost X 26, GEL4 diamonds equal zero for 117% blue A and D with 2 more event buildings with ??? stats. Gold level would get you 143%.
NOTE: Would use potions to even the event building Blue A, these are SAJM numbers, so for different eras, the event buildings will give less but less is needed as the opponent has less too (but they still got a lot)
This is how I am looking at buildings in my city and my costs. Yes it takes goods and time but for the train, I gain BLUE with a RED tradeoff. For the Druid Temple, gain RED and BLUE. The brutal part for SAJM (the other higher eras too), very high numbers for opponents.
My goal, beat E12, nego the last 4, 4200 goods a week max, 20 diamonds. Both of my worlds I can beat E11, so anyone in Modern or Colonial, here are my stats to give you some numbers
ME BLUE 287A/235D-potions to make 285D, tanks + 7 Rogues
CA BLUE 215A/175D-potions to make 215D, champs + 7 Rogues most of the time
E11 I use the attack fort + 30 more D potion in both worlds
will probably beat E12 with the temple and forts it has
Once I can get E12 done, more SBC and touch ups so I may not need forts, I don't see the need to make anymore forced changes (like adding SBC, DC = no deal, will get Virgo BPs but don't plan to plant) to beat E13. The % changes for the opponent E13 to 16 are drastic (for everyone), not worth the effort when I can just nego. This is where I am drawing the line. If I beat E13 in 6 months, whoopee, E14 is worse, this is where I don't see the value to keep poking and prodding my city.