I would be veeeery careful playing with margin on the HK futures... Tried them recently. Nice in that it's a very homely timezone - But otherwise... Well... Let's just say I trade the DAX for a living now, and the DAX is a warm lamb compared to the HSI. Was looking to scalp those futures for like, about half an hour. I think after that I was down like 14K something, no kidding. Thank goodness it was just sim-trading. Don't go heavy on the HSI unless you're clear of heart problems and any other problem, like vertigo. If you don't get vertigo, try looking at the HSI after it's just risen 30+ pts in the last 30 seconds or so. Completely new feeling. Yippee... Good Luck in Hong Kong. May grace be with you.
There may be an added layer of complexity if you use all the avlb. currencies. I know I always have some margin on non-USD currencies where I am in the red no matter how small the amount. Don't know if being in the black offsets the reds or not. Never could figure it out. Geo.