Abrac
No doubt the Cup is feminine, but while the M is on the Cup, I don't believe it refers to the Cup necessarily, but to Melchizedek. That's the key to the riddle.
I'm not so sure now the scene on the Ace has anything to do with the Graal. Waite doesn't say anything definitive in the PKT. It might, but I don't see any reason it has to be a consideration.
From the quote above, "...behind the undeclared priesthood which is according to the Order of Melchisedech..." In that whole quote he's contrasting the invisible order to the "official" order. I think that's what the M represents, it's a hint that points to the "undeclared" or invisible priesthood of Melchizedek.
I'm not so sure now the scene on the Ace has anything to do with the Graal. Waite doesn't say anything definitive in the PKT. It might, but I don't see any reason it has to be a consideration.
From the quote above, "...behind the undeclared priesthood which is according to the Order of Melchisedech..." In that whole quote he's contrasting the invisible order to the "official" order. I think that's what the M represents, it's a hint that points to the "undeclared" or invisible priesthood of Melchizedek.