I just tested out your new guide, left a reply over there on that post about my experience with it, since it might be useful to others too. :)
On another note, along the way, I also ran some more capture tests with my stream broadcaster (Xsplit). It is currently not possible to capture the game with the translation overlayed on top of it without capturing the entire screen space, but that function's a privacy risk we almost always avoid using since if anything sensitive pops up over the screen in that area it will also get captured and displayed. We typically capture by application process, not by screen-space, as such.
It IS possible to capture the game application, then also capture the translation application on top of that, but the translation application capture weirdly covers the whole screen as black when this is done. (There is technically a game behind all of that blackness lol.)
It is possible for me to then Chroma-key out 'Black' on the translation application capture to let the game be visible, but the text is kinda painful to read in this situation.
If you want to make this program more-accessible to streamers, here's what I suggest... It would be nice if we could customize how the translation overlay displays itself.
1. Customizable background color. If I could control the background behind the text to be a different color (like green). then I could easily chroma it out cleanly. (Or heck, just give the option for a transparent background.)
2. Customizable text color. If I could change the color of the translated text itself, I could pick a color that stands out more-easily on top of the game, especially after chroma-keying the background out.
3. Optional text border. If I could add a border around the text, that would help it stand out atop the game as well.
4. Optional text shadow. Again, would help readability.
Here's a quick mockup of what I'd find ideal personally, if those four customization settings existed for the overlay function:
Even beyond streamers, these suggestions could just be a nice way to customize things for any users. Your approach of putting white translation text in a black box works for now of course, but these are things I would hope for in the future. :)
EDIT: Ah, with a bit more tweaking of how strongly the chroma-key was told to react, I was able to capture just the black box and not black-out the whole game screen. 
That being said, it will sometimes blink the whole screen black for the capture display due to how the black chroma-keying is working to cull out the rest. That would be quite unpleasant for viewers if it keeps up. I might be able to tweak further to stop that from happening, but the customization ideas I shared would solve it for good.


