This is
really interesting - I've been after "the capacity of a pot" for some time now!
Do you know if your 700kg (in a 750kg pot - it's very sensible not to overfill, I reckon!) is a fairly normal sort of capacity?
It is specifically the size of one of the original pots used at Mdina I'd really like to know about, I can't imagine you'd know that, but might you have a rough idea?