Doug's machine was a D, not a G or F so not a WW.
According to Brig. Gen Ken Bells book (100 missions north) , "D" models often filled the 2 and 4 position in a WW flight (Or indeed the nr 3 as well), carrying CBU or iron bombs.
Bell mentions a flight of 1 "F" model leading 3 "D" models on a WW flight to JCS 51.10 outside Puc Yen, a flight commanded by Thorsness. The flight got sepearated over the target, and Bell (flying nr 4) has few kind words about the idea of trying to follow a lightly loaded "F" in a fully loaded "D" model.
Nice book as well.