What we're considering "screentime" here:
Simply put, any time Godzilla is present on the screen, even if he's not the direct focus of a shot. Can you see his spines? Screentime. He's on a TV? Screentime (literally). Camera pans to and from him in the space of a second? Screentime. The only thing I'm not counting are still frames of something we've already seen, so the pictures Ford is shown during the presentation in 2014 aren't counted, nor is the frame of Godzilla's spines shrouded in mist on the monitor of Monarch's submarine in KotM. This is the approach I took with 2014 and I got exactly 10 minutes of screentime. You can view that here to get an idea of how we're applying this to KoTM's scenes.
I went through a cam of KoTM (don't worry, it's a pretty clear one) doing the exact same thing I did for that video. How much screentime did I come up with?
I don't personally care much for the numbers themselves, but I know some people do. The only reason I took the time to get his screentime in the first place was because of hyperbolic claims that he only had six minutes of screentime back in 2014. I Think there's more to it than just numbers--the impression of more screentime is thanks to Godzilla's story relevance early on and him having more scenes peppered throughout the first 45 minutes of the film. Plus, there's so many different ways to judge screentime. You could judge it by only scenes where the monsters are the focus, how much is given to the other monsters, how much time the monsters share with each other, etc... What do you think? I'm expecting to get about the same amount again in GvK.
I'm not uploading the compilation for obvious reasons, but I'll do it again once we the film is out on video. Even with a high definition copy I can't imagine the totals changing more than 2 seconds, though.