Suggestions for a safe-n-fast charger for a bunch of 6th gen iPod Touch Devices?
Excess amperage cannot "force" its way into a device (that's the danger of excess voltage).  A device will only receive what it draws.
That is an interesting question with a more nuanced answer:


'Smart' USB chargers, like those found on Amazon, determine the amperage they provide based on the draw trends of the plugged-in device; as long as the device is drawing, they will provide.  However, some can detect and identify the sharp drop-off of draw that accompanies the end of the charging cycle and cut power from the port.

You can find more info about this kind of thing from this answer:  https://electronics.stackexchange.com/questions/121366/how-do-usb-charging-and-smart-charging-ports-e-g-ankers-poweriq-work