VERY nice sun don. If i could give you a few suggestions.
1) in my experience and research, low lighting is a myth. No matter where they are placed they will thrive if fed meaty food enough.
2)take it off the rocks and place it on the sand so you can feed with the "cup" method. A sun with that many heads is going to be VERY hard to feed each one individually. Much easier to put a "cup" over it and shoot as much food in as you want without fouling your water.
3)to get it to open try putting the cup over it and squirting a little frozen cyclopeeze soaked in selcon or zoecon mixed with a few ml's of tank water. Try it a few times each day. By the 2nd or 3rd day it should fully open. It needs to eat right away. Waiting 1-2 weeks for it to open is IMO why so many do bad in our homes.
Start feeding right away and keep us posted, that is a great piece!