I have no problem with a PDF manual, just look at the masterpiece in DCS A-10C. The flight manual is 669 pages long with very nice layout and images, and the GUI manual is 226 pages. Then you have the install guide at 26 pages and the short manual at 21 pages...
That's 942 pages. And they are well written and packed with info. I don't dare think of the time it took to write them. Talk about study sim
At the other hand, the "interesting" instruments and routines from a combat sim perspective of a Spitfire should be rather quick to describe, and then just include a PDF copy of "The Most Dangerous Enemy" to read up on the Battle of Britain
