Questions about specifics on firearms

[banger12]

At present I think it is more likely than not that I will CTB and I had some specific questions regarding details about use of firearms that I couldn't find adequately answered in the megathread and comments. I will likely need to resort to a handgun because I live with others (although I likely won't CTB within the home, but still) making a shotgun not an option. In the comments on the megathread it was recommended that revolvers above .38 caliber were the best bet with JHP rounds. Money is tight for me currently so when I decided to look at options (my choice will likely be a .357 magnum revolver) I noticed that the cheaper ones all had shorter stubby barrels. Does that matter? What is the ideal barrel length? Furthermore, theoretically, would one have to place the barrel as far into the mouth as it would go or should there be at least a little distance? Aim confuses me. I'm clueless about firearms and human anatomy and aim. Does quality matter? How would I tell quality? Sorry, this is dumb and rambling but I used the search function and i felt there were still ambiguities but maybe im just stupid.