Not sure if this answers anything. Larger ships I'd use one major block as a base and scaled up to the size you want with small ones added in for greebling. Since the app is much more limited than professional modeling software such as (Blender, Maya,3Ds Max, Modo) you'd have to get pretty creative using blocks in other ways to get the shapes you want. Or wait till there's blocks that suit your needs (I do take suggested block types). Here's a larger ship from an older update.
