The DA/SA debate is overblown.
Every trigger press is the same: consistent, smooth, 80/20 with the last 20% being a point of focus for having your finger flat and the pull as flat as possible, riding the trigger through the break and the shot, holding the trigger to the rear, then slowly riding it forward to the reset. All while maintaining a good grip and clear front sight.
If my firearm switches to Single Action mode, the only difference is the distance that my trigger finger travels to achieve the same results.
No matter what firearm I am using, the trigger press is the same: consistent, smooth, and then worked to reset.
Headshots at 25 yards are no problem with a DA Sig or a DA revolver. If you have the luxury of time before a shot, cock the hammer. If not, don't sweat it and rely on the fundamentals. Anyone that tells you to waste the first shot, even if his name is Jeff Cooper, is honestly full of crap.
As fishbed said, there is only one correct trigger press, and it doesn't differ from firearm to firearm.
The Travis Haley links earlier are some of the best pistol shooting videos on the net in terms of quality information in the amount of time presented.