My general obsevation, now that I think about it carefully, is that there are far more MDG large bottles around than Mdina ones.
I also trust John's opinion on the matter of pawmarks more than anybodys, including my own.
I have managed to photograph a genuine signature I have, it's not straight, the word glass actually curls over the side of the base and onto the body of the charger.
The size of his writing varies between different pieces too.