He rarely signed anything. He had a strong dislike of doing so.
It happened on a few things that were exported to the states, because the importers demanded it, there were a few things that did end up with signatures, because they were experimenting to see if they sold better, I believe - hence many Japanese globes from Mdina have signatures, and pieces of Seaward, from the early days at IoWSG, often have them.
I'm afraid I'm not very up on the matter of weights, I've never taken much interest in them.