Sorry guys for not following the thread and replying.
The i777 is slightly bigger than the i9100, but not much. This is one of those times where the "just a little off" 3rd party stuff works out to our advantage.
I haven't really used the spare battery charger part yet, so not sure when it knows to be "off"
I use one at home on my nightstand strictly for charging, one at work for hooking into my pc. No problem with data connection and as long as you're not being heavy handed, you can style use the touchscreen while docked.