There are practical limits to what you can do within a budget, even a budget as vast as PJ's. He fudged as far as possible by casting short-ish actors as hobbits, and then the hulking JDR as Gimli, so that relative to one another they come out OK, and only require trickery when onscreen with Big Folk and Elves. But that means that you are stuck with the relative heights of Frodo (described as "taller than some [hobbits]" in the book) and his cousins, Ent-draughts notwithstanding.
Of course, that sort of detail also isn't really the sort of thing PJ ever cared about much anyway; not nearly as much as the Workshop's assemblage of True Geeks (for example, in a detail almost nobody would notice, Pippin when he rides back into Hobbiton at the end is wearing his black surcoat with the Tree
and the Crown above it.
Before:
After:
