Wow, that's a tough question! The first choice would be to follow directions if any packages have them.

The PK material is the safe one of the lot. I don't think you'll burn anything with that. Mixing it into the media as you pot up would be best. If not that then mix it in as deeply as possible after planting. About one tablespoon per pot.

Ammonium sulfate will burn the roots. I think the strongest safe rate is about 1 tablespoon per 2.5 gal applied once a week. Half that rate is safer and probably just as good but you'll have to decide if growth rate suits your needs.

The micronutrient mix is something I can't help you with. It depends the material and whether it's water soluable or not. It is possible to apply too much and damage the plants. I had that happen with a controlled release this summer.

Thank you, fruitnut! Always helpful =)

I would use a fertilizer formulated for acid loving plants ( anything fertilizer for azaleas would do) and follow directions on the label - i.e. 1 tablespoon for every 4 inches of growth etc..