The smaller mould gives you a better form factor, more barrel than disk, for many cheeses. Stilton type blues, for example, would be better in your mould. And, as you say, they pack better because the barrel shape is more efficient use of shelf space. Hmm, must look into a 4.5 inch mould myself. I've just got room for my latest buttterkase, and then my cave is full! Oh oh!?