Reeeeally? That's interesting. I was basing my assumption off the Invasion of Char cinematic, where General Warfield et al look out the front and downward. You don't see any of the vessel from their view, suggesting they're at the front. Moreover, the Escape from Mar Sara cinematic suggests the bridge has windows going all the way around it, not just in the front.
If you're right, that gives further credence to your estimated scales.