Wow! Those mushrooms are huge!! I'm presuming they won't be that big in the final version otherwise it's going to get complicated seeing anyone in the raid especially with more than one resto druid using them. Blizz have already posted to say that the healing output is meant to be capped at 33% of the casting druids health per mushroom - split among the targets it hits when it blooms (so 100% of our health if we put down 3). So I guess enjoy the OP shrooms while they last!