Sure, I might try that.
I think I have noticed something else that I am doing. My left arm fingers are weak, so, for a sling shot reload, I grip the pistol with my left hand and tilt it to the right and release with my right hand. If gravity has any effect, the rear of the barrel will settle against the right side of the slide, which will make the gun shoot left. Maybe if I tilt the gun to the left and try to release the slide, the rear of the barrel will settle to the left, consistent with the later shots.
I think the horizontal movement of the rear of the barrel is about 0.002", but I will check it again. It isn't any .005-.008" like I've seen on non-CZ service pistols. At 100 yards, one or two mil at either end of the barrel will make 1 or 2 inches difference, but adding the clearance at both ends is still only 4 inches or so. I may be chasing the wrong solution! I may try just rotating the gun around the barrel axis with no other changes and see what happens.
If I can't find a mechanical reason for the 1st shot high left, I am thinking my trigger finger may be the culprit! Or initial grip versus next shots, something like that.