No glue on the bricks, just fishing line. The top is made of wire hangers and I did hot glue the middle to keep them in place better. I'd be very weary of putting legos over the crib unless they are all super-glued together, too many little pieces to fret over. It's also surprisingly heavy.
I started with bending/cutting the wire hangers to pair the outer rim planets to the central ones. Then I hung the outer rim planets and used longer line as I went to give it that spiral effect. The planets are full of pennies to balance them out.
The ships I just fit in where I could. I've got a y-wing to add now and I've been unsuccessfully trying to build a mini-scale medical frigate. I'm also keeping an eye out for the last 3 planet series at a reasonable price. I might do a parallel spiral with those.