I applaud your effort and truly wish you the best of luck!
I'm unclear if you are trying to get the company to allow regular employees to conceal carry their personal firearms while on duty or are trying to make a case that certain high risk guards should be trained and allowed to carry a side arm while performing certain tasks. If it's the latter I apologize that I didn't catch it when I skimmed through your letter and you can disregard my following rant.
Maybe I'm just extra cranky today but...that's a lot of words there! I couldn't bring myself to read the whole thing and just skimmed. I've worked closely with security personnel for several years and have to say I would seriously fear for my life if the vast majority of security that I have worked with were allowed to conceal carry personal firearms on the job! They were mostly police officer flunkies or wannabes. Yes we had the retired and even active duty officers working a second job but most were down right scary!
I'm sure different security companies hire to higher standards but from my experience and stories I have heard I tend to believe that it just might be a good idea not allow security guards as a whole to conceal carry personal firearms while on duty! I can certainly see the company's point of not wanting to deal with their "unarmed" guards producing a personal weapon and shooting bad guys.
Again, The best of luck!