Not too shallow. I think Jeff's concern is just that, like any other skill, you can't get a few on-line opinions from strangers (even well-trained trainer-type strangers) and really become proficient at armed self-defense.
For that you need to buy videos from Paladin Press.
Just kidding. There are many good book and video resources out there that can at least give you a grounding in what you should learn, but the best training is in person from a reputable instructor. Scarcity applies, I live fairly far away from the big name schools so travel costs are a factor. I have also not been fastidious in taking advantage of traveling seminars and all the local training available. But (aside from my military exposure) I have gotten the basics and do practice them regularly on my own and with like-minded friends.
At the very least, take advantage of the range facilities and opportunities you are aware of. If it is an issue of not knowing where to look for other options and privacy is a concern (as it should be), I would suggest PM-ing some of the mods on this forum with some more details of where you are located so they can maybe get you going in the right direction.
edited to add: a) I hope that's ok mods, and b) I usually carry 1 spare in case of a freak mag failure