Quine's Holism - Confirmational and Semantic

Quine takes the smallest units of empirical confirmation to be, not individual propositions, but total theories (i.e. large collections of propositions). And the issue of what to take as a unit of empirical confirmation, for Quine, seems to be intimately bound up with the question of what to count as a unit of meaning. He writes (1951, pp. 39-40):

The totality of our so-called knowledge or beliefs ... is a man-made fabric which impinges on experience only along the edges ... A conflict with experience at the periphery occasions readjustments in the interior of the field ... But the total field is so undetermined by its boundary conditions, experience, that there is much latitude of choice as to what statements to re-evaluate in the light of any single contrary experience ... If this view is right, it is misleading to speak of the empirical content of an individual statement ...

And again, in a similar vein (1951, p. 42):

The idea of defining a symbol in use was ... an advance over the impossible term-by-term empiricism of Locke and Hume. The statement, rather than the term, came with Frege to be recognized as the unit accountable to an empiricist critique. But what I am now urging is that even in taking the statement as unit we have drawn our grid too finely. The unit of empirical significance is the whole of science.

If this is a correct reading of Quine, one reason he might have for rejecting the analytic is that it requires us to acknowledge a smaller unit of meaning (and sameness-of-meaning) than a total theory, and Quine does not think it makes sense to talk about such smaller units of meaning because there are no smaller units of empirical confirmation. This is a pretty radical kind of semantic holism: it's not just that the meanings of our individual statements (or other smaller chunks of language) depend on the meaning of the total whole theory containing them, but that these less-than-theory-sized chunks don't have meanings at all; only whole theories do. Nonetheless, it is strongly suggested by certain passages.

Here's my question. Suppose Quine is right that the smallest units of confirmation are theory-sized. And suppose, like him, we are keen to tie meaningfulness to confirmability in some way. This could motivate taking theory-meaning to be primary and sentence-meaning to be derived. But what additional motivation does/could Quine have for taking the further step of denying meaning to anything other than whole theories?