In theory, when you're outside the U.S. you can't buy Vanguard mutual funds, only ETFs. If at some point you must update your address, I believe they would not allow you to purchase further shares in mutual funds - only ETFs. Your existing holdings could still be held or sold, but not increased.
So for that reason, I'd strongly favor ETFs in your case. Since ITOT and VTI both hold 3500-3600 stocks, their contents seem like a very close match - but you can still tax loss harvest between them owing to different fund names and index. Note at Vanguard you pay $7/trade to buy ITOT but $0/trade for any Vanguard ETFs. So while ITOT has a lower expense ratio (0.03%) than VTI (0.04%), if you invest $10,000 in ITOT you're paying $7/$10,000 or 0.07% in fixed costs which wipes away any benefit of the lower expense ratio.
So go with VTI, since that entails the least risk of your international address becoming a problem. As a side benefit, any brokerage can accept ETFs, so if you needed to transfer those shares it will be easier than if you own VTSAX (which cannot be transferred to another brokerage).