Some Questions about Structures

I have been making structures for quite a while but recently I have been working on a really big one, but it seems that it might be too big since the latest piece I added to it doesn't seem to generate half the time. The main part of the structure is a bunch of floors stacked on top of each other. I had to come up with my own way to stack floors without the floors getting randomly rotated when the structure generates. I was wondering if there was a better way to do this. Also I was wondering if anyone had some documentation or something explaining how ancient cities and trial chambers work, since thier code is a bit different from what I am used to but seems like its what I need do to get the other part of my structure to work.