一米 vs. 1米半

一米 vs. 1米半, area ratio is 1:2.25

So with the same print pixel density, 1.5m version should have 28-29MP. On top of that, the quality of each pixel from 5D2 is worse because lens is not perfect (so that higher pixel density will result in worse pixel quality). These two factors certainly make the large print worse quality.

A fair comparison should be printing the photos to the same size. And I can tell every one that the 5D2 photo will be better so no need to waste money for test printing photos.