Like Vought, Grumman also included a folding horizontal tail in their single-seat A-6 proposal for the Navy's VAL program.* The benefit was demonstrated by pulling three A-6s off the production line, fitting two of them with mockups of the proposed tail, and packing them together as closely as possible. Grumman claimed that the resulting spot factor of a folded Intruder was only 25% greater than that of the smaller (albeit nonfolding) A-4E Skyhawk used as a baseline. However, the winning Vought proposal that became the A-7 Corsair II had a spot factor that was 5% less without the optional horizontal tail fold and almost 13% less with it.
* See http://thanlont.blogspot.com/2008/08/single-seat-6.html