I recommend you consult a lawyer. Always understand the difference between "the law can be flouted and probably safely gotten away with so long as I don't piss off anyone powerful" and "this is legal."
This of course only pertains to federal law; states have their own laws, and said laws usually prohibit being armed while intoxicated - regardless of the legality of the intoxicating substance.
I strongly, strongly believe you are overconfident in your interpretation, particular when I read the provisions regarding possession which may be a seperate crime from say what was written on the 4473 at the FFL.
But I'm not the one you have to convince. I pray you are never in a position you must do the convincing.
I do not believe I am an authoritative enough of a professional to convince you, even were it that I had time to type a more complete explanation. Again I recommend you consult a lawyer, and preferably one that has worked in this area. My opinion as a rando on HN has no legal bearing on the justice system.