Thank you for the reply, Jamstigator. I've decided to use the 85-watt CFLs and, after discussing the matter sans context with a mechanical engineer friend, plan to use the smaller 4" ducting and fan in conjunction with soundproofing material in the upper chamber.

The cabinet's completion will require several more weeks, MindYaBidness. Pictures of it now would feature wires, scattered sawdust and power tools. I'll include pictures of the final result in my grow log, when I finally begin it. Watch for titles like, "Help, they're all brown!"

Also, feel free to ask the off-topic question in the thread. I don't think the mods will mind since most of the discussion so far has been relevant.