EDIT: Faster and more reliable display wake appears to be achieved by adding the igfxonln=1 boot arg as described
here. The EDID injection described below does not appear to be necessary.
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WARNING: After running with injected EDID properties described below, I have noticed a change in sleep/wake behavior. Sometimes my system does not sleep when left unattended and sometimes it wakes to dark screens. I have removed the injected EDID properties until I have more time to test. Without injected EDID properties, my system reliably and consistently sleeps/wakes. Displays may wake a few seconds more slowly, but I'd rather have reliable sleep/wake than occasionally have displays wake a few seconds faster.
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My displays wake from sleep even faster (now almost immediate) after injecting EDID (created with Hackintool) for each of my displays. I learned this tip in another forum that can't be linked to this post. I will add this to the config.plist that I include with a future EFI update attached to post #1 in this thread; however, users will need to generate their own EDID patches that are specific to their displays.
The EDID for each display is injected with graphics property key AAPL0X,override-no-connect, where X is the display number.