I'm not sure how big it is - the smaller half is still hanging out under the rock, but I'm guessing it's probably going to be 5" or more.
I did buy the RSM, just opened it last night. That's a hell of a deal from DPV, wish I'd known about it. I managed to get a decent price from AC, and got the stand new off of craigslist for really cheap, so it wasn't too bad.
What's the deal with the lights? I have no experience with T5s, so I don't even know what the bulbs look like. These look like PCs, but they say they are 55w T5 Power Compacts? I want T5s, not PCs.