I have read this: Multiple custom-set-faces and custom-set-variables in emacs
An answer is:
If you are manually adding custom faces, keep it in custom-set-faces.
As for having multiple (custom-set-faces ... ) or (custom-set-variables ... ) lists, I have just tested this (in Emacs 23.1). They do work - Emacs will process all lists - however, if you then use M-x customize-face to add a new custom face (similarly for a variable) and save it for future sessions, Emacs will combine all the lists into one. So, you should probably only keep the one.
I would like to know if there is any way to split a custom-set-variables
call into smaller calls. Example: I would line to split this
(custom-set-variables
'(custom-enabled-themes (quote (solarized-dark)))
'(custom-safe-themes
(quote
("8aebf25556399b58091e533e455dd50a6a9cba958cc4ebb0aab175863c25b9a4" default)))
'(package-archives
(quote
(("gnu" . "http://elpa.gnu.org/packages/")
("melpa" . "https://stable.melpa.org/packages/"))))
'(package-selected-packages (quote (solarized-theme)))
)
into
(custom-set-variables
'(custom-enabled-themes (quote (solarized-dark)))
'(custom-safe-themes
(quote
("8aebf25556399b58091e533e455dd50a6a9cba958cc4ebb0aab175863c25b9a4" default))))
(custom-set-variables
'(package-archives
(quote
(("gnu" . "http://elpa.gnu.org/packages/")
("melpa" . "https://stable.melpa.org/packages/"))))
'(package-selected-packages (quote (solarized-theme)))
)