Build them in pieces (make it modular) and save as multiple templates (especially the really big projects). You can make stairs as a (separate) template (only down fall is you have to plan ahead when you add the stairs.
I do this a lot when I’m building different castle/ alters and such. Need a hand built wall section save as a template, need a tower, save as a template. Get enough pieces and you have a modular castle builder.
