[RacingManiac]

Regardless of transitioning from primary or just a draw, the technique should not vary aside from moving away from the primary. The difference is in a transition the support hand is dropping/throwing the primary away from your work space and shooting hand going for the holster and gun. Depends on the urgency you might have to start from one handed shooting. Regardless though the drawing to aiming phase should be very similar. As soon as the pistol left the holster the muzzle should be forward and for me its coming up to my center mass and punch forward to your work space. I think for some teaching defensive shooting if the target is close enough to be an immediate threat they would actually start firing(while backing away from the target) as soon as the muzzle is pointed down range, then as they draw away from the threat they go to a proper shooting stance. If you are not transitioning, the support hand will meet the weapon as it get to the work space...Pistol shooting needs lots of practice and muscle memory and you need to work on sight acquisition....also note shooting RDS like a C-more to shooting iron sight there is going to be a difference in the sight plane. Slide mounted RMR/Docter sight is start to get more popular, and they have less of a difference in sight plane...

EDIT:
This is mainly from a hip holster mounted on the shooting hand side, should be relatively similar to dropleg. My IPSC rig to regular belt rig are both hip mounted, with the IPSC rig extend down a bit more as its made for a 7" open Hi-Capa.