I don't know the answer, but I'm in the process of making a castle cake for my daughter's birthday party this weekend. I'm only baking right now so I'd be interested in hearing the answer as well. Here's a bump in hopes someone else will have an answer for you.
I think it depends on what you make the turrets out of. I think some use cake, some use rice crispies treats. I used gum paste/fondant combination around paper towel rolls, so the turrets weren't very heavy and I used royal icing around the bottom and attached to the sides of the next cake layer and they were very solid, actually very hard to pull off. (Picture in my photos)
Quote by @%username% on %date%
%body%