I never temporarily install fonts so I'm no help!
Nexus:
Right click on not installed and you can add the folders where your fonts are stored. I have one font folder in my scrapbook supplies where I've thrown all downloads over the years.
Right click on sets and you can add sets and groups. I had a set for handwriting, one for titles, etc. I think you simply drag the font to the set. I lost all my organizing in my computer crash so I simply printed out all my fonts. It took a lot of paper, but paper is cheap and now I can see them all.
But I don't have thousands of fonts either. I think I could set up subfolders on my hard drive inside my font folder for typewriter fonts, title fonts, handwriting fonts etc but I haven't tried. That would be one good way to never lose organization of downloaded fonts (if it works). You can also organize fonts in ACDSee per Kayla Lamareaux's ACDSee class on her site. I haven't tried this but I do really like ACDSee and might try it at some time.
Now you know everything I know about fonts. Which isn't much, haha!
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