I would say the first visible sign of Connally in distress occurs at Zapruder Frame 223.
As well as a slight change in Connally's Facial expression, and Irrespective of Zapruder's Camera Jitter, you can see the gap space between his Jacket Lapel and his Neck Tie increase dramatically.

Yes that iz koz the slug struck at Z218, & the mini-lapel-flip iz a sign of the jacket bulge being well formed at that time (ie Z222)(ie 4 frames at 18.3 fps).
And the Z218 corresponds to Lattimer's bulge tests & hiz lapel flip (taken with his 30 fps still camera)(alltho Lattimer's slug landed at in effect Z219)(except that Lattimer's erroneous jacket (the lapel was very very long) & erroneous slug location (too high & allso the slug took a chunk out of the lapel) suggested that Z218 was the true number in 1963.
Z218 had jfk exaktly halfway along the sign (here i mean halfway along/throo the period where jfk dis-appears & re-appears).