Wait, this is interesting. I just dove into how TD works, and unless I missed something, in the current implementation you should only get ~5% boost unless there exists an AI at an era tier higher than you.
I ran another test ( see "Game2001B Gameplay Log.ods" spreadsheet in attached zip file for tech-by-tech result logging) to size TD beaker impact in the extreme case of running with no traits ("normal" and Complex both turned off) and with WFL turned off. I expected game progress to be slower than usual, but was very surprised by how much slower and by how much gold I earned per turn (to the point that towards the end I spent most turns building beakers directly in my 3 largest cities as "science pseudo-buildings").
Custom Game and Map Set-up
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For full set-up details, see "Game2001B Set-up Details.txt" in attached zip file. This zipped (".7z") file also contains calculations spreadsheets, game saves, etc.
1) Code Base: Ran whole test on SVN11103 (V40.0.1158) from January 12 to 25
2) Key Game settings: Emperor difficulty level with 6 AI opponents (but see "cheat" note below), playing as Iroquois led by Deganawida.
3) Key Map Settings: C2C_World at Standard size, Long Game speed (4000 turns), Medium Sea Level, Start Everywhere.
4) Key gameplay BUG option settings to isolate TD impact: Complex Traits off, "normal" traits off , TD on , WFL off, Tech Trading and Brokering both off.
5) WB "cheats" to improve the generated map: Good starting location on first try. Deleted a near-by AI that would block my expansion, flattened 1 mountain to a hill, added 1 deer, 1 obsidian and 1 squash at my planned first 3 city sites.
Results Summary:
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(1) Completed Prehistoric Era (finished Sedentary Lifestyle) at turn 540 in 7629 BC (much much later than expected). Averaged across the Prehistoric Era, TD supplied 22% of the beakers (with Infrastructure buildings at 43%, slider gold settings at 33%, Science builds at 1% and free bonus beakers at 0%. At completion of Sedentary Lifestyle, I checked AI technology progress using WB, and all 6 AIs were ahead of me (in the range of 3 to 10 techs).
Assuming my guesses below are more or less correct, this could bridge the discussion about TD only providing 5% or less TD benefit. Spreading a 22% TD beaker boost evenly across 6 AIs needs each AI to provide a 3.7% TD benefit to me. The actual technology leads by AI were Aztec at 10, Rome at 7, Inca at 6, Neanderthal at 5, plus Portugal and Egypt each at 3.
2) Completed Ancient Era (finished Classical Lifestyle) at turn 972 in 319 AD (much much later than expected). Averaged across the Ancient Era, TD supplied 13% of the beakers (with Infrastructure buildings at 26%, slider gold settings at 51%, Science builds at 10% and free bonus beakers at 0%. At completion of Classical Lifestyle, I checked AI technology progress using WB, and all 6 AIs were ahead of me (in the range of 4 to 13 techs).
As above, spreading a 13% TD beaker boost evenly across 6 AIs needs each AI to provide a 2.1% TD benefit to me. The actual technology leads by AI were Neanderthal at 13, Rome at 10, Egypt at 9, Inca at 7, Aztec at 6, and Portugal at 4.
3) Played the early part of Classical Age, completing 8 more technologies by turn 1026 in 583 AD. Averaged across Classical Lifestyle and these 8 technologies, TD supplied 8% of the beakers (with Infrastructure buildings at 17%, slider gold settings at 53%, Science builds at 22% and free bonus beakers at 0%.
I also noticed that I was earning much more gold than normally, running at an average 95% science slider setting (and a solid 100% for all technologies past Chiefdom). The gold numbers rose significantly by era, averaging 17 gold per tech in the Prehistoric Era, 1,297 in the Ancient Era, and a mind-boggling 4,284 while learning Classical Lifestyle and 8 more technologies.
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Guesses I'm making about TD mechanics. Can anybody verify or correct (or politely suggest I stop making wild guesses, or ask for more information)?
1) Each civilization that already has a specific technology provides TD beakers to each other civilization that is just starting to learn that technology.
2) There are TD calculations and parameter values to determine and limit how much each "donor" civilization supplies to each recipient.
3) There may or may not be additional TD calculations and parameter values to limit how much a "recipient" civilization can receive from multiple donors as TD beakers.
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Oops! Forgot to attach the attachment.