This is difficult to assert. I know quite a lot about Judaism as a result of my interest in jewish history (particularly the theories about anti-Semitism), but the '6,000,000' does not come directly from the Talmud (which one? Babylonian: I presume?). You see the '6,000,000' number has two potentially sources as I understand it: population statistics or the rabbinical concept of the Guzma ('exaggeration'). Both arguments are largely conjectural unfortunately since as far as I know there has been no clear evidence as from whence the early '6,000,000' claims (they date as early as 1881/1882, possibly earlier, if memory serves) took their number. It is one of those underresearched, but vital, areas that one occasionally finds in any branch of scholarly inquiry.
Now the population argument is that it was asserted (I've never found an exact source for this) that there were roughly 6,000,000 jews living in the Russian Empire in the 1880s (or possibly just the Pale of Settlement). It needs to be remembered that this has been tabulated using religious criteria so when a jew converts to Christianity, be it Catholic or one of the Orthodoxies, then he or she is no longer reckoned to be a jew. I am not sure about jewish atheists, but I presume the Russian authorities still classified them as jews given their general association of atheism with satanism (i.e. opposition to and/or denial of Christianity). Anyway: so according to this argument, which is conjectural as far as I know, there were 6,000,000 jews, i.e. followers of Judaism, in Imperial Russia at this time hence the claim.
Now in the Judaism argument the concept of the 'Guzma' comes of importance. The 'Guzma' is a rabbinical concept, which is used to express the scale of a catastrophe ('shoah'), i.e. the number of jews who have suffered and/or died, in terms related to the tales of the Written Torah. Now the 'Guzma' relies on the Talmud Bavli (I forget the precise citations as the thing is huge) in so far as it calculates the extent of a 'shoah' by taking the number of jews the Bavli says came out of Egypt with Moses in the Torah (600,000) and then multiplies it by a number to express how serious and awful a 'shoah' the event is (from what I've read usually 1 to 10 given that jewish audiences became less accepting of insane figures at least as early as the 19th century). Thus 600,000 x 10 = 6,000,000 (i.e a truly biblical shoah). So in this argument we have rabbis explaining the scale of a 'shoah', which they cannot know, by using the concept of the 'Guzma' to create a number which can then be passed along to other rabbis around the world as a representation of the scale of the 'shoah' which has occurred or is occurring: hence the '6,000,000' claim.
Both arguments certainly have some truth to them and it is, in my opinion, probable that both had a hand in creating the '6,000,000' as a means of explaining the scale of the 'pogroms' (localised anti-Semitic riots would be far more accurate as they weren't government sponsored despite the still common assertion made on the basis of Simon Dubnow's work in the 1930s). However in the context of the 'caust: I think we have to suggest that the latter is of far more importance than the former in terms of influence as the former would have changed considerably by 1941-1945, while the latter was maintained in Judaism.
If you go looking for the concept of the 'Guzma' and other associated concepts: you will probably have a hard time finding them. I didn't even know they existed until I stumbled across a reference to them and another jewish custom (Lashon Hakmah ['The Language of the Wise']) in an obscure 1929 translation and explanation of the 'Tales of Rabbah-bar-bar-Hannah' by J. D. Eisenstein, in which he mentions and explains it in passing in order to explain one of Rabbah-bar-bar-Hannah's veiled stories.
The numerology arguments you should really leave out as these are from jewish mysticism (the most famous example of which is the Zohar) and operate as a different, sometimes opposing, tradition to the halakah and aggadah of the Mishnah and the two Talmuds (the Talmudists and the Kabbalists have and still do spend a lot of time fighting each other on various points of Judaism). In essence arguing the '6,000,000' comes from the numerology arguments is absurd, because most rabbis are not kabbalists or mystics [hence place little value in numerology] and certainly jewish mysticism had little to no impact on the orthodox and secular jews (I include the conservative and reform jews as secular) who were at this time (and still are) the mainstay of Judaism and the jewish community. Thus I cannot see how you can maintain that jews created a '6,000,000' figure out of special regard for the number '6' as it would have been near impossible to spread such a number as the ultra-Orthodox are not known for their friendliness and social networking amongst non-ultra-Orthodox jews.
Slightly off-topic (I apologise): don't use Hoffman on Judaism. He isn't a good source and he has a long history of distorting (and even simply making up) things about Judaism and jews in general (for example there is a G.I. Joe character, Dragonsky, listed as a jew in his 'Judaic Communists' article, which gets routinely quoted on anti-Semitic sites and by anti-Semites in general). Hoffman is largely plagiarising (in terms of arguments, which he then tries to try and add modern sources to support even if reading the literature proves them to be bogus [for example the 'raping of three year old girls', which he probably got from reading August Roehling's, 1885 [I think], 'Der Talmudjude' or the doubled [in size and content] French translation and addition by one of Drumont's associates]) Johann Andreas Eisenmenger's 1700 'Entdecktes Judenthum' (Judaism Uncovered), who, unlike Hoffman, actually spoke Hebrew (as far as I know Hoffman doesn't speak Hebrew or Yiddish despite citing sources in both languages) and was an expert in his subject [which Hoffman despite being well read and a quote farmer isn't by any measure]. It is worth picking up the English translation of Eisenmenger (which Hoffman has recently reprinted and charges an outrageous $200 for [you can pick up an original German first ed. for $1700-2000]) rather than buying Hoffman's 'Judaism Discovered' or 'Judaism's Strange God's'.