Can't open links from this computer and will admit I don't know much about the airplane and glider dynamic however I can only assume that the pulling aircraft would not be loaded with supplies or troops. I don't know how weight is modeled for troops or supplies in c-47s but I can venture to guess an actual fully loaded C-47 wouldn't be able to haul a second fully loaded dead weight a/c.
Sure it could although at the cost of airspeed. The Goon only needs to provide forward thrust since the glider provides the lift. In theory, a Goon could carry more if either engine power were increased or increased wing area with the same power, but losing airspeed. In the case of the glider, you are increasing the goons carrying capacity by essentially increasing the amount wing area and lift it's forward motion produces.
Additionally, in the case of AH, 10 troops is 1/3 a C47's troop capacity but am not sure what the weight of supplies are, that could be a limiting factor.
SEsaber