I would not be comfortable bringing 7 months worth of cash with me, and official oversea transfers from Canada cost at least 2.5% FX fee + other fees on top. I made some more research and seems there's no way, at least from Canada, to avoid that FX conversion fee, unless I use a complicated system that would required an extra bank transfer before I can send the money abroad.
I will bring my first month worth of expenses in cash (including the extra rent's safety deposit) and then use the Vietnamese "mafia" system ($5 +1.5% fee, no FX fee) to have money sent to Vietnamese contacts in Saigon who will deposit the money into a Vietnamese bank account and will allow me to withdraw as much as I want with the bank's ATM card.
Even though I'm from a socialist Canadian province, I'm very capitalistic in my way of thinking *but* I can't stand banks. That half hidden FX conversion fee of 2.5% is an example of their predatory practices and only now some local governments are forcing banks to disclose these fees (like on credit card statements in Quebec). So as a matter of principle I will do anything to avoid the Western banking system. Even in my city, I'm willing to pay for bus tickets to go to my bank's ATM to avoid withdrawal fees even though it might be more expensive in money and time, just to show you how much I hate giving even $1 to banks.
As a "hobby", I do credit card churning, which means applying for credit cards to get free rewards and then cancelling, For me it's not even for the money, it's for the pleasure of extracting $300-400 from a bank every time I do it. Of course I need to do this with moderation because your credit score takes a hit every time (in North America, we're using credit monitoring companies like Equifax that will give you a "score" based on your credit history).