An update, a further 28 days later. I have just researched Trading Center 3.
I used a mix of Mana and seeds, including using time instants to speed up Ezero production. It still seems slow at times, but I'm using the KP to upgrade Ancient Wonders. Vortex of Storage is now lvl 6, and halfway to lvl 7. I have used spare Orcs to upgrade GA and MH to lvl 31, and added another two levels to my Timewarp.
At first I considered saving all my production to unlock Trading Center 3 research, but in the end decided to build the three of each Large Ship first, as that greatly helped the Settlement resource production, and I could boost Ezero with time instants. I am using time instants now until Trading Center is upgraded to lvl 4. I will then use the Portal Profits I have saved up, currently 1525%, which equates to 3,129,300. I will still need to produce it normally for a while after that. Ezero is still what will take me the longest to produce to finish the chapter.
As I upgraded workshops and residences to lvl 38 I also removed quite a few to make space.
Current layout here at ElvenArchitect
I will be removing the excess culture and population to fit the Small ships, and provide an update again when I research Trading Center 4. The large ships are certainly helping with Settlement production, so hoping the small ships will further benefit.
I still don't have the BTG, but the increased guest race production it provides is probably worthwhile if you have it.