... NORMALLY carry a handgun with a 15/16/17 round magazine (and no spare magazine) ...
I don't normally carry a pistol without a spare magazine. Resolving a magazine-related functioning issue is generally most easily and quickly resolved with a spare magazine.
Think a magazine-related functioning issue can't occur? Spend more time at the range watching LE and CCW folks qualifying with their carry equipment.
Sheer 'capacity' doesn't cause me to lose sleep. I've carried issued pistols with magazine capacities of 15, 14, 12, 9, 8 and presently 7 rounds. I've carried personally-owned pistols with magazine capacities of 12, 10, 9, 8, 7 & even 6 rounds.
I used to carry a 6-shot .357 Magnum as an issued revolver, and still carry a revolver off-duty more often than not ... and it has a 5-shot capacity.
So, capacity doesn't cause me to stay awake at night thinking about it.
Knowledge, awareness, skills, accuracy, firearms maintenance and a suitable carry method for my needs continue to occupy my attention, though.