Just FYI. Last time I ordered books from www.bookcloseouts.com and delivered to Toronto. The delivery time was 3 days only and saved a lot of shipping charge.
Next time you can order and send to US or Canada address if you have friends or relatives coming back to HK.
I also like to shop at paddyfield. I love their bookbuck incentive. Besides, they can usually deliver books within 2 weeks after placing order. They only charge to your credit card after delivery.
For books which request delivery over 4 weeks, you may call them to request delivery of the rest of the books first and they can arrange to separate delivery of books in the same order.
I did try rainbowXXXX. I think prices are similar to paddyfield but it takes longer for delivery and choices are limited.