Just so you know, OFX's rates to send USD are exorbitant. To be specific, they wanted to change 2% more than the actual exchange rate. 2% is a bloody lot, in the same neighborhood of sending money with Paypal or Western Union.
HSBC (the evil bank) took 0.5% above the actual conversion rate, plus 250 HKD for the transfer fee.
Next time I'll investigate whether Citi or SCB will do a better conversion to USD or have lower transfer fees. I'll also check out ajohnso2's suggestion, though this time I didn't really have time to mess around with test transactions. Or I'll live dangerously and use Bitcoin to do the transfer.