There is a background of W's Tractatus that we cannot forget: Frege's Begriffsschrift and Type theory formulated in W&R's Principia Mathematica.
W's interest on logic (see e.g. Michael Potter, Wittgenstein's Notes on Logic (2008)) has been stimulated by the discussions with Frege and Russell on logical matters, and Frege's Begriffsschrift is "a formula language, modeled on that of arithmetic, of pure thought."
3.323 In everyday language it very frequently happens that the same word has different modes of signification — and so belongs to different symbols—or that two words that have different modes of signification are employed in propositions in what is superficially the same way. [...]
3.324 In this way the most fundamental confusions are easily produced (the whole of philosophy is full of them).
3.325 In order to avoid such errors we must make use of a sign-language that excludes them by not using the same sign for different symbols and by not using in a superficially similar way signs that have different modes of signification: that is to say, a sign-language that is governed by logical grammar — by logical syntax. (The conceptual notation [the "concept-script"] of Frege and Russell is such a language, though, it is true, it fails to exclude all mistakes.)
It seems to me that the purported "Russell's misunderstanding" has some reason in W's text.
Having said that, it does not seem to me that Ramsey share Russell's point of view; see his CRITICAL NOTICE (1923):
it is possible that [Mr Russell's Introduction] is not an infallible guide to
Mr Wittgenstein's meaning. "In order to understand Mr Wittgenstein's book," says Mr Russell, "it is necessary to realize what is the problem with which he is concerned. In the part of his theory which deals with Symbolism he is concerned with the conditions that would have to be fulfilled by a logically perfect
language." This seems to be a very doubtful generalization; there are, indeed, passages in which Mr Wittgenstein is explicitly concerned with a logically perfect, and not with any language, e.g. the discussion of 'logical syntax' in 3.325 ff.; but in general he seems to maintain that his doctrines apply to ordinary languages in spite of the appearance of the contrary (see especially
4.002 ff.). This is obviously an important point, for this wider application greatly increases the interest and diminishes the plausibility of any thesis such as that which Mr Russell declares to be perhaps the most fundamental in Mr Wittgenstein's theory; that " in order that a certain sentence should assert a certain fact there must, however the language may be constructed, be something in common between the structure of the sentence and the structure of the fact".
Ramsey discuss at lenght this "fundamental theory", based on the central concepts of: picture, fact and (logical) form.
We must now turn to one of the most interesting of Mr Wittgenstein's theories, that there are certain things which cannot be said but only shown, and these constitute the Mystical. The reason why they cannot be said is that they have to do with the logical form, which propositions have in common with reality.
Also he says that "The feeling of the world as a limited whole is the mystical feeling" 6.45). But I do not think we can follow Mr Russell in deducing from this that the totality of values of x is mystical, if only because "The world is the totality of facts, not of things" (1.1). And I think that 'limited' gives the key to the sentence quoted above. The mystical feeling is the feeling that the world is not everything, that there is something outside it, its 'sense' or 'meaning'.
See also the conclusion of FACTS AND PROPOSITIONS (1927):
In conclusion, I must emphasise my indebtedness to Mr Wittgenstein, from whom my view of logic is derived. Everything that I have said is due to him, except the parts which have a pragmatist tendency, which seem to me to be needed in order to fill up a gap in his system. But whatever may be thought of these additions of mine, and however this gap should be filled in, his conception of formal logic seems to me indubitably an enormous advance on that of any previous thinker.
My pragmatism is derived from Mr Russell; and is, of course, very vague and undeveloped. The essence of pragmatism I take to be this, that the meaning of a sentence is to be defined by reference to the actions to which asserting it would lead, or, more vaguely still, by its possible causes and effects. Of this I feel certain, but of nothing more definite.
The statement: "the meaning of a sentence is to be defined by reference to the actions to which asserting it would lead, or, more vaguely still, by its possible causes and effects" seems to anticipate the second Wittgenstein.