I have it working, but it's a little odd because it says "with a loud crack, the wand snaps" when it runs out. There's no broken sceptre graphic, so I'll probably have it just remove the enchantment when it's done. I think making it unlimited would make a mage run a little too easy.
I remember it being like that, and that you can sell the empty sceptre as jewellery. Perhaps the name just needs to change once the charges have been used up. However, it’s illogical that the feedback refers to a ‘wand’ rather than a ‘sceptre’.
Unlimited charges wouldn’t be a good idea – I agree with you there.