When using soul trap on creatures where the soul size doesn't match up with the soul gems I have in my inventory, what exactly happens then? If I capture a soul that is too small for my soul gem, do I automatically waste a large soul gem on a small soul?
So, do I have to be careful which souls I trap in order not to waste any soul gems? Or can I happily trap everything and the souls will only go into the correctly-sized soul gems?