Robin,
I use "assess" instead of "scan" because I like the implications of that word more than what I see many people doing when they only scan after a string of fire. I think we are speaking the same language here!
We also agree that just because something is "common" it doesn't make it "best". (Weaver stance, for example.....

).
******
In regard to the Seated issue with 5 O'clock carry: Blackhawk has recently announced their version of the quick disconnect holster mount. The way this works is that you can mount a hard point receptacle for your holster just about anywhere you want. On your belt, On your vest, under your desk OR on a hardpoint in your car. While the system is designed so that one holstered weapon can be moved from belt to chest to car to desk quickly, efficiently and safely without unholstering, there is no reason why the mounting point and holster cannot be attached somewhere for dedicated use. With this system, you can mount a holster inside your vehicle and when you enter it, transition from you 5 IWB holster to the permanent hardpoint holster in the car. This both eliminates the comfort issues AND facilitates a faster draw while seated and seatbelted in the car, if necessary!
-RJP