It sounds like you also have to buy special cases for the charging mat to work on various devices... I'd just plug each thing in as needed.

If you're sitting by a outlet you can use the tablet while still plugged it can't you?
we use our laptop on the coffee table and just plug it in when we use it. The old battery doesn't hold a charge anymore, but we don't carry it around when using it so plugged in is fine for us.