Moxon vise - size?

For those of you with Moxon vises... what size did you go with (between the screws), and what influenced your decision?

I'm debating whether to build a 'full sized' version, with 25-ish inches between the screws to allow for any future case work, or to go smaller (16-18" between screws) for what will most likely be the majority of what I actually need i.e. boxes, drawers, etc.