I'm running H&G in coco as well (DTW), but with a different approach.
Multiple feedings per light cycle (3 during flower) - 3 gal smart pots.
3ml/gal of Cocos A/B
1ml/gal of Dynagrow Protekt silica
3tsp of magnesium sulfate per 30 gal
Occasional CalMag if I think it's needed.
1ml/gal of...