Late game, is it better to use 8x8x8 or 12x12x12?

So far I've been just making 8x8x8 blocks to minimize coolant usage. But now I'm wondering if it would be better to use 12x12x12 to conserve paint.

So I guess the real question is: in the big picture, which is the more scarce resource, coolant or paint?

If coolant is cheaper, maybe it's better to paint and cut 12x12x12 blocks. If paint is cheaper, maybe fine to stick with 8x8x8.

Another consideration is that a lot of building ratios seem designed for 8x8x8 so using 12x12x12 means more cutting, more complicated logisitics, and thus more space.