That's pretty close. For me, the black malt is over the top with astringency when I want to get it real dark. I use a de-bittered black like Briess Blackprinz it's like 550L and doesn't taste like burned coffee to me.
I also like mine to dry out to around 1.012, so I sub out a pound or so of LME/DME with dextrose.
I also use some Briess Midnight Wheat for color, flavor, and body.
Check out the "Darth Vader" thread.