Everything is measured in X, the height of the letters in OVIOS. Pick how tall the cube should be against the text. The gap between them is always 0.3 × the cube's height, so it scales with the cube. C is what your current board uses. Click an option and the rules sheet below updates to match.
These use the same proportions: a version without the tagline for tight spaces, the stacked version for square spaces, and the cube on its own.
These are actual pixel sizes on screen. The tagline drops off below the minimum width, and red marks a size that's too small to use.