In addition to weights Pirelli also sold Vasart dishes and advertised in three sizes. 10oz 14oz & 18oz. Although the information is a little ambiguous as it links Millefiori to the dishes. I am not aware of 'flattened paperweight' type of dish made by Strathearn having been made by Vasart and it may well refer to the use of chunks of Milleiori that usually look like blobs of colour. See the first advert here for the type of piece they sold
http://www.ysartglass.com/Pirelli/Pirelli%20Glass.htmIt would be interesting if someone could check in their collection the weights of various pieces - due to the gift shop nature of Pirelli's retail operation this will probably be the more common posy bowls etcetera. They also sold the Vasart paperweights in the same three sizes.
I would like to include this information for Vasart in the Scotland Glass catalogue when I expand them from Ysartglass but lack a large collection of small Vasart to check.