I leared something new today, XDE 20k bulbs are one in the same as XM 20k DE bulbs, cause thats what they sent me, and printed on the bulb it says XDE250, but came in a XM 250 20k box. The color is a bit too purple for my tase, but its not burnt in yet, since its only run 3 hours so far. I can't wait to see its real color, I also have an oportunity to get Phoenix 14k 250w bulbs through a group order at about $50 a peice, so I'll go look at a locals tank that has them running, and see how I like those. I had some issues with lots of heat radiating into the tank, but I easily fixed that by hanging a fan on either side of the pendant pointing at each other, creating a whirlwind effect, and dispersing the heat.
As far as aclimating corals to the halide, I don't know if I'm doing this the right way, but I have the pendant suspended 10" over the water, and I am running the lights 3 hours a day, then every 4 or so days, I will increase the light cycle another hour, till I get to 8 or 9 hours per day. After I get the cycle to a full time, I may try and lower the pendant another 2" or so, and see how that works with heat and how even the lighting is from side to side.