Interestingly enough, the only(allegedly) reported case of Argyria I could find involving a CS solution made by current standards(ie, 20ppm +/- w/distilled water) was reported as a localized condition. That is to say, that the discoloration was specific to one area of the skin such as the throat in this case.
That being said, I should also add that the report did not come with photo's or any form of verifiable data. And so I'm really not sure how helpful this as far as documented sources go.
On the issue of warning signs, reports seem to indicate that the build-up of silver can apparently be observed in sellect areas such as; the whites of the eyes, finger nails and/or under the tongue and gum-line areas prior to the onset of the condition. Though I'd caution against false positives in such cases as fingernails and the gum-line(for example) can exhibit a bluish to purple hue under normal circumstances.
As for the developing effects, the evidence seems to suggest that Argyria develops quite rapidly once a person has accumulated sufficient silver in the body to form deposits. Which usually manifests itself once they are exposed to the sun.
Hope this helps
PS. I've been taking 6-8oz of 20ppm CS daily for nearly two years now and so I'm wondering what you consider large amounts?