As a current double breasted blazer wearer, be forewarned that it's nearly impossible to sit down with the blazer on without it looking awful. If you unbutton the blazer two huge flaps go flying out in front of you which looks even worse. The single breasted blazer is both classy and functional and looks good when you unbutton it to sit down. I'm surprised this hasn't surfaced in uniform testing.

I wouldn't sweat the hat and shoe rules. Those will eventually morph anyway based on where your domicile is. DFW will be a boot base and PHL and JFK will be no-hat bases