For my life wizard, I chose death and trained all the way to wraith. Feint was an excellent bonus to life's already some what weak attack. Plus, if you learned spirit blade from Niles then death spells will also get the bonus so it's a good hit school for life and good at helping life get stronger hits.
till feint. or train 
till tower. id say one of the two may be the best. if possible train both 
