WM: I focus on the front sight while aiming, then the target when shooting.
That's incorrect. Your focus should never come off that front sight ever. The target should always be a general blur to you.
Keep concentration on the front sight the whole time forcing it never to move at all and you may get a handle on your flinching.
Remember... there is no recoil and that front sight should never move. Press the trigger directly to the rear and that front sight never moves.
Stance is irrelevant when it comes to getting the bullet to where you want it to go. Get in a comfortable shooting position and make sure that front sight doesn't move.
Flinching
squeezing your palms/hands just before the shot goes off
not following through your trigger press all the way to the rear
not pressing straight back (slightly pressing left or right on the trigger)
^^^ those are all bad habits that takes time over coming.
There's a bunch of drills one can do to increase their precision with shooting hand guns (which btw is hard).
My favorite is the one shot in the eye drill from 3-5 yards away:
When you hit the center of the eye.... your mechanics were on point. A little off, and you're doing it wrong... suck less.