Niiiiiiiiiice! I keep being tempted to make tacky references to how much bigger yours is than mine! ;-)
I completely agree with you about the texture of the parts. I would hate it if I was making say, a Naboo cruiser, but for this, the rough finish and slight stair-stepping just add to the effect. You'd expect a little weathering from all the particles being pulled into the BH. When painted up, the pieces really look like pitted old metal.
Oh yeah, as for the uprights on the center section, I know the horizontal bar I've added is extra, but no one will be able to see it tucked in there, and I really want something to hold the uprights in alignment. Sometimes thin pieces seem to bend, and I think that would be more noticeable than the extra bar. I've also added a support piece on the connector section to hold up the cross tube. Again, it's not going to be tha noticeable, and I'd prefer the extra stability.