I could not resist. this video cracks me up every time.
I only skimmed the thread but a few ill toss in my 2 cents.
I could not disagree more about getting a full size gun. a compact gun is way easier to conceal overall. the barrel is down your pants... barrel length doesn't matter really, but the length of the grip is what sticks out. In the pictures on the first page you are standing completely up right, I could put an 18'' shotgun down my pants and you would not see it until I moved. If you cant get the job done with the 15 rds in say a glock 19, then you are screwed anyways. I am a firm believer that the best gun, assuming you only have one, is the gun you cant see yourself leaving home without. open carry aside, you will probably be more apt to leave the house without your heavier, bigger full sized gun when its hot and you just toss a t shirt on and head out the door. as far as IWB to OWB, it is just as easy to hide in either if it is hoodie weather, and OTW is usually more comfy. to each their own, and this is a with all due respect. Not trying to start a pissing match just my thoughts.
Second, a 9mm is more than adequate. something like a 124grn p+ hollow point and your good to go. This is coming from a die hard .45 guy too. the 5.56 are military uses is a "small" round too. if you get a leg it wont matter if its a .50 bmg or a .22lr. and even with the additional rounds in your average 9mm pistol compared to its .45 counter part, the .45 is still gunna be heavier, and that makes a longer day to carry it around.
good luck on the purchase!
ETA: .... then i finish skimming the thread and relies you already bought the gun haha. Enjoy!