I've read the FAQ on skins, however I think I am still missing something.

Say I want to make a redone line-art for an existing species such as a gryphon. Can I use one Rainbow Jar to make that line art AND color it, or do I need two Rainbow Jars to make the lines and then color them? Additionally, is it possible for me to make the lines available to everyone as a skin but reserve the specific coloration for me?

Here is an example of the type of line art I would be interested in making: http://i1118.photobucket.com/albums/k617/Lykouros/Escutcheon%20Gryff%20Adopts/Leviathan_zps4d6a883c.png (my artwork, please do not use).

Any help is greatly appreciated. Thank you.

~Lykouros

You can make the lines available to others, but not as a skin, since lines would not be an acceptable coloration to apply to a pet.  You can make the lines available in the creative forum as a file for others to play with, or you can make different colorations of your lines available as skins.  I think that also answers the first question - you can't "make" lines, only a colored version of those lines.

Lykouros, you don't need anything to create and upload any custom skin. Though you will need a Rainbow Jar to apply this skin to your pet.

A skin can be shared to public or private. Private skins are available to use only for their author. You can make a specific coloration private and leave the others public.