I am still keeping an open mind on this one.
THX1138 rightly says that George Kulles' books are excellent. But we should note that the first two were published in 1985 and 1987 and were therefore based on information at that time. The later book was published in 2002 and, as Alan points out, we now have new information to study.
However, I'd like to add a few detailed points for consideration:
Nadine stated, as is often said amongst paperweight collectors,
... One of the most important is, that at all VSL weights have a low profile and a rather low dome .
But on page 62 of Kulles'
... The Less Familiar, he sated under "Profiles",
Later unfaceted Val St. Lambert examples have a taller, rounded dome.
Unfortunately, he did not show a comparative image of such a dome and he did not say whether thiose profiles were comparable to other makers. Perhaps the "higher dome VSL" weights will turn out to be later Clichy?
When comparing designs of weights, it is tempting to say that a particular pattern or usage of canes is "the same as" others seen and therefore, (also bearing in mind other factors), it indicates a particular maker. In Kulles'
... The Less Familiar, page 65, he said,
A common Val St. Lambert design has five cane clusters spaced around a central millefiori cane.
That general pattern - of five outer clusters - was also used by other makers (including modern Scottish). But the majority I have seen have had a cane cluster at the centre, not a single millefiori cane (as shown in two examples by Kulles). Could the central single cane actually be an identifying feature of VSL? If it is, then Nadine's weight is most certainly not VSL because it has a double-row cluster at the centre - and it also has only four outer clusters, not five.
One problem is that the book does not explicitly state whether there were or were not other known variations of that pattern from VSL.
I think this is all quite fascinating and is similar to the (sometimes heated) discussions over several years on whether or not Whitefriars made weights dated 1848. Anyone who checks out Kulles'
Identifying Antique Paperweights Millefiori will see, for example, on page 37 that reference is made to "early Whitefriars weights (dated 1848)". Since then [1985], proof has been given that many weights with exactly the same "1848" canes were actually made in the 1920s at the Arculus factory in the English midlands and similar weights and bottles, again with 1848 canes, were continued by Walsh Walsh (after buying Arculus) and certainly marketed in the mid-1930s. Of course, there are still various collectors who do not agree that Whitefriars did not make those items.
I am eagerly awaiting the English translation of the new book on Clichy that Alan mentioned. Although I have briefly browsed two copies, I have not properly studied any of it. So for now, I will accept that Nadine's and Alan's views on the mystery weight being late Clichy are the current favourite.