Make yourself a grid on heavy paper or cardboard as long as the mast (for instance, the foremast) is tall of vertical lines matching the shrouds. Then draw horizontal lines where you want the rat lines. Longridge (page 231 3rd line, 2nd paragraph) says the lines on the actual ship were 13 inches apart. This, if I did the math correctly, is a little over 3mm. Clip this grid behind the shrouds as a spacing guide. I find it make the work a lot easier. Some ratlines were omitted between the first two and last two shrouds. These omissions are indicated on your plan sheet #10. Good luck. You have a lot of ratlines to tie on.