Installing the theme is easy.

Inside this ZIP file, the folder names represent a variant.
The first number is the inactive depth, and the second one
is the active depth.
The higher the number, the larger the shadow. 

I didn't make variants with bigger inactive shadows,
because that might look confusing.

Folder names: "[Inactive Size]-[Active Size]px"

Inside each folder is an installation package. You just
need to open it to install it.
It should show up in ShadowFX's selector, no problem.

If you choose to change variants, just open the package of
the variant you wish to install. After you install the new
variant, reload the theme by switching to another theme
and then back.

Default package name: "TrueDepth.shadowfxtheme"

All of the file names are the same, so that the new
variant will replace the one installed. This prevents
TrueDepth variants from cluttering your ShadowFX library.

(If the names remain unchanged,) installing a new variant
replaces the file containing information and parameters of
the theme variant, but not image files from previously
installed variants. This is because of laziness on my end.
It shouldn’t affect your experience using the theme. Just
wanted to say that every time you install a new variant, an
extra tiny bit (10-35 KBs) of disk space will be used.