I use cross-draw holsters for convenience and consistency — John Bianchi's RULE #1.
I sit a lot — in chairs and in my 4Runner. Having identified no way to smoothly draw a handgun in an armchair without getting up, I ruled out strong side.
When carrying a handgun while woods walking and hunting, a cross-draw holster is, again, more convenient than strong side. The longer the handgun, the more convenient becomes cross-draw.
For all cross-draw carry except my SP101 3-inch, Red Nichols' CD-xxx series of cross-draw holsters are the cat's meow. They ride high on belt. Their design keeps holster tightly against my body. And losing the handgun is extremely difficult with or without its safety strap because of the pull-through spring system. While I have used CD-123 and CD-125 as EDC cross-draw, Mark at Lobo worked with me to create an egregiously efficient cross-draw holster for my SP101. I hope he kept it available for others.
Drill from a chair is straightforward. I emphasize smoothness rather than speed.
Drill when standing is again emphasizing smoothness rather than speed. Since the revolver is concealed, having it materialize unexpectedly is whatever advantage I might have. Drill emphasizes shooting from belt level. I am little concerned with antagonists 15 yards away. Instinctive shooting practice is geared toward an antagonist within 15 feet. I also practice pivoting and sliding. I don't draw across my body. I pivot or slide my position that I am shooting along side. Think of a duelist's position relative to his opponent — but gun cross-drawn and at belt level. Additional range practice is for shooting up to 50 yards. SP101's bobbed hammer I can cock only with a two-handed grip. The ideas being my hormones will be dumping into my system at a slower rate, allowing me perhaps better single action shooting. Oh yes, I enjoy the change of pace.
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Parenthetically, Nichols' design is so flexible that the CD-xxx series can carry revolvers and semiautomatic pistols without any issues. I have no idea why it is not in production.