So, while I feel like this is a problem I'm going to ultimately fudge and forget about, I'm suddenly very interested in trying to find scale appropriate stuff to go with my Heat Ray Hokkaido. So in the movie he's from he's around 328 ft tall. This makes the figure just over 1/560 scale. I think a 1/500 building is close enough as I'm using this Godzilla as my Heisei era general stand-in. So everything from Return of Godzilla through Spacegodzilla. He ranges quite a bit in height over that period so should look just about right.
I also picked up a Super X Gashapon that's 1 inch long, making it roughly 1/1000 scale if what the internet tells me is true that the Super X is 88 ft. But then I look at this still from Return of Godzilla (Godzilla is supposed to be 260 ish ft here) and I just don't buy that the Super X stood on its nose is 1/3 as tall as the big guy. The Super X seems more in the foreground and seems like if it were in the same plane as G it would be closer to 1/4 or 1/5 as tall if stood on its end.
Anyway, this is all to circle back to me saying "whatever" and just fudging it. I'll get some 1/500 scale buildings and call it a day. But uggh, scale models, why must I obsess over this?