I used mold 300, 301, 302, 303, and 270. If I had 'em, I'd add the small pipe mold. I will tell you that I did make some custom molds of the floor pieces. You might take a gander here for some more pics of sci-fi terrain I've done.

If you dig around ironhands, you'll find some good step-by-step instructions (I think he calls them STC's). A lot of what he builds for the sci-fi pieces are made using things like plastic wiring boxes, old Necromunda panels, and pieces for GW's relatively recent Cities of Death. That's not to take anything away from him, but you might find that they are easier than you think.