Hi Joe
Its quite difficult to tell Vasart and Strathearn apart as Strathearn was
effectively Vasart under a new owner. Same workers, same factory, same
tools, same canes. Here are some clues to help you tell them apart..............
Vasart weights usually have the canes thast are raised above the
ground and apart from the very late ones have the rough ground base.
Strathearn weights have a fire polished base and the canes are flush
(or nearly so) with the ground.
The base photo of yours shows the rough grinding and the canes are
raised above the ground so its a Vasart.
Murano weight bases are invariably flat ground and polished.
Re telling the date from the design - not possible I am afraid. The designs
were set up on the plates by the glassworkers wives and a few others and
they were free to design what they could with the canes that were available.
Hope this helps
Best regards
Derek