Pops would have more insight than me, but I like trying to figure things out. I don't have Synod, so I can't attempt the infinite deck.
It seems to me that for the Synod trick to work, you need to be able to afford to keep buying cards so you can trigger drawing cards to 11. At that point, you have 10 coin cards and one card that just keeps drawing from your deck.
So you need cheap cards: Militia, Serf, Collect Taxes, Courtly Intrigue all can cost 5 or less easily enough. If you use the starting hero with the Wealthy Patron, you can turn food into gold.
Then you also need to acquire money. Collect Taxes and Wealthy Patron will help you on your way. I suppose Loan would be useful too. When you're ready to start the purchases, buy Loan to get that extra kick. You may even restock it so you can keep it going. Who cares about how much you pay later when you have infinite turns and can end the game?
So how close am I, Pops? Well, looks like he posted already, but I'll keep my original thoughts and see what he says.