While Wingard didn’t exactly share how the two of them will be able to look each other in the eyes, Wingard referenced a moment from Kong: Skull Island as one possible “out.”
In the film — which takes place in the 1970’s — John C. Reily’s character says that Kong is not done growing yet, implying that he will hit a real growth spurt in the some 40 years between Skull Island and Godzilla Vs. Kong.
Adam Wingard spoke to IGN at Comic-Con where the Death Note director made it clear that the size difference between Kong and Godzilla is something he knows about, meaning it will likely be a non-issue by the time the movie begins filming.