This is great work, Bryan .
We could draw a line from "subtlety" to "simple living" if it was otherwise established, but I do not see that it is.
The closest I have is in The Double Indictment (section 2) Lucian has Zeus complain "I myself have to do any number of tasks that are almost impossible to carry out on account of their subtlety (ὑπὸ λεπτότητος)" -- which may be enough to draw it all together and preserve the manuscripts reading.
I see LSJ cites Plato, Laws, in their definition, so maybe applicable:
Ἀθηναῖος: τί δέ; σώματος, ὦ ἑταῖρε, εἰς πονηρίαν, λεπτότητά τε καὶ αἶσχος καὶ ἀδυναμίαν, θαυμάζοιμεν ἂν εἴ ποτέ τις
Athenian: And how about plunging into a bad state of body, such as leanness or ugliness or impotence? Should we be surprised if a man of his own free will ever
LSJ defines that use as "thinness, meagreness, of body"