Welcome to the Forum.
Its Powder, wad, ball.
If you load the wad over the ball there is nothing to keep it in place except the slight compression it gets from being shoved into a slightly smaller hole.
The first shot from the gun will have enough side blast that it can easily blow the adjacent chambers wad out of the mouth of the cylinder.
Tucked nicely between the ball and the powder it will stay where it needs to be to lube the bore as it passes out of the gun and to act as a shield for the powder from any small spark that might try to get past the pressed in ball.
Speaking of sparks trying to get into the adjacent chambers, if one does make it it can cause the often mentioned (but rare) "chain fire" where chambers not aligned with the barrel fire.
Although there is still some debate about the causes of a chain fire most shooters agree that a loose or missing percussion cap on a loaded chamber is the most likely cause.
For this reason, it is a good idea to look at the nipples on the unfired chambers after firing each shot.
Sometimes, a loose fitting cap will be jarred loose from the recoil. If this happens the cap can fall off of the nipple opening the door for a chain fire event.
You didn't say whether your new pistols are brass framed or steel framed.
If they are steel framed, you cannot "overload" your guns chambers.
If they are brass framed, it is a good idea to keep the powder loads to the moderate or light side.
It's not that the brass frames are unsafe however they are not as strong as steel.
Heavy powder charges can loosen the cylinder arbor or drive the cylinder back into the frame hard enough to eventually indent the circular ring in the frame right behind the cylinder.
If this happens the cylinder will become loose.
