How can I get `emacs --daemon` to load the Spacemacs configuration?

I have configured my ~/.emacs so: It either launches default emacs via the default init.el, or runs the Spacemacs init.el

I run Spacemacs via a spacemacs shell script, ~/bin/spacemacs

#!/bin/sh
export USE_SPACEMACS="1";
emacs $1

and this is the content of ~/.emacs

(setq use-spacemacs (getenv "USE_SPACEMACS"))
(when (> (length use-spacemacs) 0)
    (setq user-emacs-directory "~/.spacemacs.d/"))   ; defaults to ~/.emacs.d/
(load (expand-file-name "init.el" user-emacs-directory))

How can I run emacs --daemon with the configuration from the ~/spacemacs.d/init.el? I may have to adjusted to disable stuff like the server-start and other such options.

For the meantime I have settled on starting Spacemacs in background screen terminal and running the emacsclient commands in my regular terminals.