>>55170718As long as the sprites are evenly spaced to be 1/4th of the width and height, it doesn't actually matter how big the sprite is. I had to adjust the size for Hilda's surfing spritesheet because it was too big to fit wailmer and the fishing rod. The game won't cut anything off if the size is different from vanilla sprites.
>>55170742If you need a base that's centered, the Hilda character mod in OP's google drive should be good. If you change the size of the sprite sheet, just make sure to adjust the centers of the sprites as well.