What do with excess mana? Wouldn't it be fun to use it somehow? I propose that mana toys be sold at merchants and found in boxes. When you fuse your mana into it, the toy grows in capability. Say for example at 1000 mana it activates tier 1 of its
scripts on up to tier 10. If they have some functions, like say every once in a while they can spit out a bit of mana at you (very small amount compared to what you put in, it's not a mana batter) or they can channel a tiny bolt that takes 1 hp and causes irritations. The toy begins to catch fire and put itself out, which gives you a chance to warm your hands then wash them off. Maybe the mana toy starts grabbing your wands and consumes them for more mana, then they have a little display where the imbedded spell went? It could be loads of fun and something to do with your spare mana.

Dragons r Real