Try the Oxford dictionary, obsolete definition dating back to 1690 - "Regulated" has an obsolete definition (b) "Of troops: Properly disciplined" and then "discipline" has a definition (3b) applying to the military, "Training in the practice of arms and military evolutions; drill. Formerly, more widely: Training or skill in military affairs generally; military skill and experience; the art of war."
But of course this is all a red herring argument because the preface does not even purport to limit the amendment. I'm just speaking hypothetically that, even if it did, you are still wrong. There is no serious academic thought that remains in favor of a collective rights view of the Second Amendment. Even Lawrence Tribe agrees with you.
In the Miltia Act of 1792, Congress details the organization, the armament, and the training of the Militia. Now, I don't understand why you would only choose one of these areas, training, and say that's what was meant by "well regulated" -- and use a 1690 definition to back you up.
I guess we'll just disagree.