For my own view I think this is more than possible but 1) the tats would probably be visible, I can't imagine anything in the alchemist made ink makes it go stealth mode when you put it on skin, and 2) I'd personally limit it pretty heavy because you're basically putting the magic version of a highly experimental weapon on your body. I can't really imagine that's safe, even if you're not constantly drawing from your own aether whenever you use it, you're still conducting powerful forces directly through your body. I'd personally go that route for maybe one or two 'signature spells' that the character would basically want to have constant access to in case of emergency or something.
