Switch to octavo format

document.tex

@@ -1,4 +1,4 @@
-\documentclass[paper=a5,fontsize=11pt,parskip=half,twoside,DIV=16]{scrbook}
+\documentclass[paper=6.5in:9.25in,fontsize=11pt,parskip=half,twoside,DIV=16]{scrbook}
 
 \KOMAoptions{toc=flat}
 \KOMAoptions{toc=idx}