krod, the moment the trigger is pulled it is completely disengaged from the cylinder stop. The BEST way to check the cylinder alignment is to cock the revolver and run a bore rod down it to see if the forcing cone and cylinder align. Most do.
A poor boy way is to shoot the pistol with cast bullets with paper a few inches to either side of the flash gap. If you get lead spray you have misalignment. If you get excess leading on the cylinder face you have some misalignment MAYBE. Maybe not.
I have an old Iver Johnson bicycle works 38 S&W that was my Great Grandmothers that is as lose as a goose on the cylinder but, that's the way it was designed. This revolver is easily a hundred years old, and it still shoots true.
The woman has been dead so long I don't remember her, and I'm 60 years old. From what I hear, if she were still around, and had this revolver in her apron pocket, I would not want her shooting at me.
Cylinder play is all about the tolerance in the fit between the cylinder stop, and the cylinder notch when they are fully engaged.