Massad Ayoob disagrees with you and who are you to disagree with Massad Ayoob?
View: https://www.youtube.com/watch?v=X0QuB2v5rLw
C'mon. No one is going to refute anything Ma says in a video because we are all asleep within 3 minutes. The dude is just so boring to listen to. His books are great. His verbal delivery is just terrible. Those ones with him and. . . Hacklethorn (I think) are even worse.
He is just that 1980's slide-carousel type speaker.
As far as which to use - use what you like. Honestly, this Weiner-measuring thing is overblown. You can overthink a SD scenario to death. Some guys carry 2-3 spare hicap mags. Odds are it's EXTREMELY unlikely that you'll ever pull your spare mag, let alone ever get to the 3rd 15-17rd mag.
Spend time at the range. Spend time at home just practicing your stance and hold and dry-fire and draw. That alone will do wonders.
Complete aside - in the last 15 years, my range time has gone to near-zero. Family comes first. Business second. Shooting a distant 3rd. Golf? What's a golf??? LOL
Anyhow, me and hte boys went to the range on JumeTeef. Youngest was using the G44. (Which is in .22. But a G22 is in 40. A G40 is in 10 and a G10 is a type of grip for a 1911.)
AAAAANYHOW, after about 30-40 min, he had a single .22 that would not fire. He kept loading it again and no-go. We were shooting mostly a steel A target at 50 yards. Just to force everyone to slow down and shoot with a lot of thought.
I tell him let me try and see if I can get it to go BANG. I literally put the .22 in the mag. Inserted, dropped the slide, pushed out my hands, NEVER F'ING LOOKED, and DING! Center of target. I never thought it would do anything but CLICK in the first place.
Both of them had their jaws open. I didn't do squat. Muscle memory did. I couldn't do that while thinking 5 out of 10 times. The time my eyes were on target was less than a second. I happened to be staged in the correct direction and it was what we were doing for 30 min already.
What you want is to get your body to a baseline of talent without your conscious brain kicking in. Then the conscious brain can do the higher-level stuff while things like,
"Where is the gun?"
"Where are my sights?"
"What shirt button should I aim at?"
"Did I clear my holster correctly?"
don't even reach your conscious brain.
About 20 years ago, I had a hunt like that. Boar hunt. I hit him with a 308 and he wouldn't go down. The guide said "hit him again." I raised and fired. He was down. I went to clear my bolt action. Not only do I forget that I chambered a round after the second shot, I never thought about the first shot. 100% muscle memory loaded that gun. I have a faint recollection of the bolt going home after the second shot. My buddy that was with me said it was just automatic.
I don't profess to be a master, because I'm not. Those are just two crazy examples of the type of muscle memory you want. Don't think, do. (And I really do like hte G19 platform. It was my first gun and the one I have most muscle memory with.)