Most efficient form to summon Trolls in big numbers?

[Rytek]

i like the summon snakes spell for meat shield. size 4 and decent hp and mr 12 makes them good magic decoys to protect high gold units like knights. spells will tend to target the snakes more than your knights. being poison resistant and having a decent morale is a bonus. use the snakes as magic decoys and shield infantry to decoy arrows.