Adding to the chorus here of C1's opaque and inconsistent transfer timeline. Like many others, I tried doing a 1k test transfer to Singapore Airlines that went through instantly. Followed that up about 30-45 mins later with a much larger amount - 271k - and nothing happened. My C1 account showed the miles as deducted from my account but there was no record of it on my SA account, and I didn't get the email from C1 either stating the transfer was complete (which I did receive for the test transfer).

Called C1 right away and they told me a lot of the same things that have been recounted by others on this thread: can take 10-15 days, we don't have visibility after it leaves your account, you can start a case but that might take 15 days too, etc etc. I ended up calling SA as well to check, and they were gracious enough to place my itinerary on hold for 15(!) days to give the points time to make their way over. Turns out I didn't need quite that long, because I just got the email from C1 confirming the second transfer and was able to book my awards travel. Took about 30 hours.

The best advice I can give folks when you see a rewards flight you want is to call and ask if the airlines will hold the reservation for you before you initiate any transfers. That one step will save you a lot of anxiety. It will vary from airline to airline though, but it never hurts to ask. From other recent bookings I've made, United Airlines offers the option of locking your rate for a fee ($10 per passenger for 3 days, and some longer options as well). British Airways held a reservation for me for 6 full hours . Still better than nothing.