I also have a question about soul trap. I know you can make soul trap 1 second or 120 seconds, but does it make a difference? If I have a 1 second soul trap does that mean the monster has to die within that time? Or when you use soul trap the effect stays until the monster is dead?
If you use a one second soul trap, the enemy must die within one second. Buffy's bow has a one second soul trap and works wonderfully on its killing shots. She has spells she uses if she wants to capture the soul of a poisoned victim while she patiently waits - those are up to 30 seconds long.