As a follow up to Part 1, I've added a basic model of the Blockade Runner, based on Mike Marincic's excellent orthgraphic drawings. I've also used his scale for the Tantive, which puts the ship at about 495' long. As you can see, she's quite a bit bigger than the scale drawing originally indicated.
I suspect that the scale of this drawing was based on the second iteration of the Blockade Runner, when it first transformed from being an early Millennium Falcon:
as you can see from the windows of the hammerhead section, the scale was quite a bit smaller than the final model eventually implied.
And now, for fun, here are some renders of all the ships stacked up together, as they might be seen from an observer standing on the ground, taking in the scale in person... (Click any, to enlarge.)