[loud incorrect buzzer]AlthoughSF_HIRESandhighresscaleexist. Which can fit his sprites size easily. Without the need to make the same size as Sonic for example. Which is the default size for characters that DON'T useSF_HIRESandhighresscaleat all.
highresscale and SF_HIRES only increase or decrease the size of the sprites, what you're actually looking for is height and/or radius, which do modify the character's hitbox.
As for Kou, there's a small issue with hitboxes which is that the levels themselves -and plenty of custom levels- do not account for characters his size, as he is notably larger than the rest of the cast by a wide margin. Certain levels he'd have to awkwardly figure out a way to squeeze through if I made his hitbox any bigger, its a good thing ERZ got updated otherwise he'd be softlocked in vanilla of all things.
TL;DR it's less about sprite size accuracy, and moreso player convenience.
Lastly, I didn't shrink him down with hires because that's goes completely against what I intended him to be like. If I wanted to make a smaller character I would have, lmao
I was so wrong on that... I forgot 