That depends a lot on WHICH old time combat planes. At first it was flown with Ringmasters. Then the TAILESS wings like the Orbit Ace, etc. These didn't turn well especially so maybe up to 30 degrees. Then when they started extending the tail ( Whatzit or Hornet) you may drop the throw to maybe 12-15 degrees. After that the 'boom' airplanes ,Voodoo, Sneaker, Big Iron etc. way down to less than 10 degrees.......The later generation maybe no more than 5-8 degrees. You'd trim them to something on the edge of a stall at full travel and no more.
Dave