Concerning the new heavy panzer grenadier squads that have 3 models attached to a single base, how many dice would an attacker have if the weapon does 1/+ damage? 1 or 3? If the answer is 3, then how many dice would be rolled if the target has already suffered 2 health loss?
 
A 1/+ Incendiary Blast weapon rolls one die against squads composed of multiple figures on a single base.