i forgot the biggest thing, patience
with sufficient lighting, strong flow, stable parameters, and clean water, everywhere is a sweet spot
My biggest hurdle was not a sweetspot. But working on re-dialing in my system after expanding by 200 gallons. I have it in low flow low light and medium flow higher light. And things did not color back up all nice until it got accustomed to the new alk and ca and mg settings.
I think within reason, water parameter settings and water quality changes in either impact this coral to a greater degree than placement.
top bottom and mine is in the middle. have you checked for any pests?