Two other works which address this subject are:
Dangerous to Man by Roger Caras, 1975 and
Venemous Animals and Their Venoms by Bücherl & Buckley, 1971
Even though both books are rather dated, they do make for some interesting
reading.
Bücherl & Buckley categorize reactions to cone stings as mild, moderate, or
severe.  Mild = localized pain with numbness and redness at the site (similar
to a bee or wasp sting).  Moderate = secondary symptoms including edema,
headache, swelling, and chest congestion.  Severe = paralysis of throat
muscles, difficulty swallowing and speaking, respiratory paralysis,
unconsciousness, and in extreme cases, death.
These authors attribute most of the known (at that time) severe and fatal
cases to Conus geographus, with Conus textile a rather distant second,
responsible for only a few severe cases.  Surprisingly, they list Conus
striatus as "reported to sting, but no actual cases confirmed".  They list one
severe case definitely attributable to Conus omaria, and at least one
"moderately severe" case each for Conus lividus and Conus tulipa.  Cases of
mild human stings were recorded for Conus aulicus, obscurus, nanus
(=sponsalis), pulicarius, imperialis, quercinus, litteratus, catus, and
marmoreus.
Caras's list is essentially the same, but he also describes Conus gloriamaris
as dangerous.
Undoubtedly much more is now known about these species than when these books
were written.

Paul M.