Rod‘s post has made me think (thanks!). In a vehcile scenario the idea is to get out of Dodge. Use the vehicle as a shield and escape the situation if at all possible and de-escalate any encounter. Probably no need to ever deploy your weapon.
If you can, that would be the most sensible thing to do. It also may not be possible in every case, and you may have to fight right from the seat you're sitting in. Ever watch some of those carjacking clips and how they set them up? Are you at least somewhat prepared to do that if you cant drive off?
Best to try to be as broadly prepared as you can, to deal with as much as you can, so that you have some previous experience and a base to draw on, should you need to do it. You cant practice for everything, but you can still be broad in your skill base and be close enough to cover "most" things. At least it wont be so strange that your loop puts you into vapor lock and you freeze up.
This all comes back around to the gun just being a part of a package deal, and while it can be an important part of that, its not the only part.
That's what I do. It actually solves a few issues, including the grip rubbing my love handles raw from the grippy grip I have on my Kahrs on long trips.
Further, I use a belt slide type holster... it allows me to move the holster back and forth on my belt to suit my position. When I'm out of the truck, I can slide it back a little (to 4 O'Clock) to get it out of the way a little, and keep large-frame autos (1911, HiPower) from printing the butt. I can slide the holster forward (to 2:30-3 O'Clock) if there is the potential for use, no matter how unlikely, and so the butt is more forward when I sit in my truck. Everyone is shaped differently... when I sit in the seat, with the pistol at 4 O'Clock, the butt hits me right in the kidney, and I tend to turn my body slightly to accommodate it... leading to poor posture and backaches. Being able to slide that holster forward alleviates this.
I appreciate some of you who say that anyone can carry a full-size pistol, which is true, and that all you have to do is dress for it... which is sort of true. Much like a pistol in a pocket, a full-size pistol buried under your clothes (to conceal it...) may or may not be the best solution. Neither one of those is going to provide immediate access and presentation. My personal solution to this is to carry a not-so-full-size pistol that I can hide well enough (within the limits of the law and my personal standards...) in a manner that allows me to access it immediately... or at least more immediately than rummaging around in my pocket or cargo pocket, or having to hike up layers of clothes I have to wear to adequately hide my piece
No matter how I dress, I can still get a solid 1.5-2 second draw, from concealment starting with my hands hanging naturally by my side. Winter is a tad slower, but only by a smidge, and I normally wear an anorak over a fleece in the winter. No matter what, its still faster than any pocket draw starting the same way, and by a good bit.
No matter how or what you carry, you need to figure out the best way to do it, so that it is readily available and easily accessed, and practice that whole presentation to the point of thoughtlessness, no matter the time of year or what you're wearing.
And you don't have to change what you normally wear to be able to carry the larger guns either. As long as you wear clothes that are appropriate for your "current" size, ie., clothes that "fit" you, its not a problem. Sizing up, can be just as bad as trying to fit into what fit you when you were 20# lighter, either way, they just don't look right, nor do they work right.
