I am looking for some advice on coral placement.

I have a plate coral (short tentacle) on the sand of my 46 gallon
(about 16 inches from the top of the tank). My lighting is 175w mh
and vho actinics.
I am pretty sure after my research that this is the right place, but
would like some confirmation.

What about my hammer coral (I think that is what it is even though it
was sold to me as a torch - it has a v shaped skeleton and short
tentacles with bomerang shaped tips. I have it towards the top of the
tank about 8 inches from the top and my lights are another 9 or so
inches from that. I have read conflicting things about this
one...some say the bottom, others higher up.

Lastly I was duped into Goniopora by bad advice from an LFS person who
recommended it to me as a fairly easy coral and a hearty one. Last
time I buy somethings without researching it first...where is it's
recommended placement? Though it may not survive anyway, but I want
to give it the best chance I can.