Your theory is totally implausible, since it is contradicted by the facts and makes absolutely no sense.
The "FBI's theory" isn't a "theory." It's what the facts say. The facts very clearly say that, based upon the time it arrived at AMI, the AMI letter was mailed at the same time and from the same place as the other media letters; it left a trail of spores through postal facilities between Trenton and Boca Raton; the guy who carried the mail bag with the letter from the Boca Raton post office to the AMI building contracted inhalation anthrax; the woman who opened it remembers the letter and remembers throwing it away; it was her job to open letters addressed to the Enquirer; there were spores in her nostrils from handling the letter; the area around her desk was the most contaminated area in the building, and Bruce Ivins was known to be a reader of The National Enquirer and kept old copies on his desk.
All you have is a belief that is totally unsupported by any facts. That makes it pure speculation, but, if you want to call it a "theory," that's up to you.
The FBI botched their investigation. Their theory requires an AMI anthrax letter, yet there is no AMI anthrax letter.
Because their theory is flawed, and because you are married to that flawed theory, you are choosing to focus elsewhere, such as on my theory.
But my theory isn’t the end-all/be-all. It’s just one example that uses existing facts. Other theories might do the above even better than mine, and pretty much *any* theory is going to be better than the one that you support relentlessly as though married to it.
Fact #1 is that there is no AMI anthrax letter. It never existed. The FBI certainly doesn’t have it. Neither do you.