Thank you for this!
So to clarify don't use the equilibrium yet or not at all until my gh and kh are correct?
Re-read point #2 attentively... You need to lower you KH and raise your GH after. So yes you will have to add GH+. That is the water you use for water changes. not in the tank.
First you need to study what your fishes requires.
I don't want to sound condescending. But, Be certain that you understand what you are doing and why, before doing it...
If you are new to tempering water chemistry. Better safe than sorry.
I would not really want to be the cause of a cataclysm in your aquarium, because I enticed you to modify something that needs somewhat a good basic understanding and cannot be done blindly.