As for the cocking of the wrists, you do have to cock them sooner than with longer
irons because the shaft is shorter. On the other hand, never cock your wrists before you even start your back swing. Concerning distance, you might wnat to try a more aggressive attack angle. To do so, bring the ball back in your stance (towards your right foot if you're right handed) and strike the ball with a descending blow. By doing so, you'll get more distance from your wedges since you're actually "
delofting" the
clubs. Give it a try a see what happens.