I am thinking this could do with some work:

1. Available in a separate repository ie like altercation/vim-colors-solarized the reason for doing this is it can then easily be used by a plugin manager (vimplug etc).

2. I would consider modifying the togglebg script to work for all four schemes, light, dark, white, black.

3. I'd consider a 24bit RGB true color only variant for neovim-qt ie like JulioJu/neovim-qt-colors-solarized-truecolor-only