Lowes and HD have angle iron aluminum you could use as a spacer. You can cut the lengths to size using a hacksaw. I don't have a canopy, but I can tell you that both my 250W pendants rest directly on the aluminum. I can touch the brackets within a few inches of the lights and it's relatively cool or slightly warm at the most.
Alltex or Radioshack may be a good source for the 8 pin connector. May want to google them for the nearest one.
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