Usually, I scale parts on the Armada mesh against pre-existing SFC models of a similar design. If there's nothing similar, then I look at the scale it was on TV or in movies (if it was) and try to get a similar scale. If not from there, then it's best guess. But usually the scale translates well for me, as it does for me when I convert over a .LWO if the LWO was originally scaled down from a default size.