As far as oranges and reds are concerned, you are right about the giesemann pure actinic not working all that well. In my experience running that bulb, it dominantly highlights greens.
My oranges show up best under 22k bulbs. (giesemann actinic plus, ATI blue plus, Aquascience 22k, Current Usa 460 actinic (worst of the 4 listed IME).)
And as far as daylights are concerned, the ATI daylight 15k (aquablue special) brought the oranges out in my tank better than the Giesemann 15k (aquablue plus.)
As far as t5 goes and LPS, I highly recommend raising the t5 pretty decently high off the tank. A friend of mine uses 4 39watt t5s over a 100 gallon rubbermaid tub:
bulb order:
actinic plus 22k
pure actinic
aquablue plus
actinic plus 22k
The light is hanging about 18 inches off the water surface, and the LPS colors are out of this world. and the polyp extension on the corals was amazing as well. I am curious to see PAR readings in that tub.
just a bit of food for thought.
-dan