Comment by LukeShu

It's a 4x8 grid, like I said. https://lukeshu.com/dump/miniwi-grid.png

Weird that the lowercase letters with ascenders are taller than normal uppercase, I didn't notice that. But yeah, the core numbers+uppercase box is 3x5 (with only "Q" violating that). And it's all on a 4x8 grid.