Need help! Rocker shaft bolt broke in head. Need removal advice

Alright, so I'm gently torqueing the rocker arm shaft bolts to the heads - following the directions and starting in the middle and working my way out and around. I was probably being over conservative and going a half turn at a time trying to torque to 15 ft/lbs when all of a sudden as I'm torqueing the center bolt, it shears off with half of it in the head.

Here is the dillemma... what's the best way to get the bolt out without tearing up my heads?

... and, what's the proper toque for the rocker arm shaft bolts for a 360? Hayne's manual says 15 ft/lbs. and Edelbrock says 25.

Thanks for your help!!