I sent a message to Fritz Wagoner asking his advice on a section of the plans. The measurements on F4 show 7" but the 1/4 scale looks more like 6".
Fritz Wagoner has built at least 2 VP airplanes and has probably the most informative web site on VP building. http://www.zianet.com/fwagoner/ Fritz also told me about the Volksplane builder's group page (https://groups.yahoo.com/neo/groups/volksplane/info) with a lot of very good detailed photos. (Note: this page has been become obsolete because of Yahoo changes in policy a new VP builder's group has taken its place. https://groups.io/g/Volksplane. Unfortunately all of the Yahoo group photos were not captured and moved before the Yahoo group went under)
Fritz informed me that on the F4 plans the 7” measurement on the plans was a misprint and should be 6” to accommodate a 45? angle at the 2” measurement fits the cockpit seat better.