Hi
newfiepicks and welcome to FlyerTalk.
My experience is not recent, and not with AC. However, there is very little experience on this board or with most of the airlines on these rewards, so I'll give it my best shot to get you started.
First, I think you will find some helpful guidance in these threads:
http://www.flyertalk.com/forum/showthread.php?t=131821
http://www.flyertalk.com/forum/showthread.php?t=373338
What I
think I know is this:
Each airline sets there own terms for the rewards. Most are NOT tightly capacity controlled. Some are. The ones that are controlled usually use the frequent flyer class code to apply the limitation.
But many airlines simply specify a certain revenue class code to be sold for HH rewards. The difference is that Q and V class, for example (from UA's class restrictions on HH rewards), don't usually sell out by the time the advance purchase deadline passes, so there are usually plenty of seats left over for HH rewards.
In fact, you can often get around the advance purchase restrictions tied to the HH rewards if you use the booking procedure I have outlined.
And that booking procedure may be at the heart of your question: Is it that you don't want to order certs prior to knowing you have confirmed seats?
If so, well neither do I, and I have always used the procedure I discuss at length in the other threads to minimize the risk/hassle factor.
It's worth quoting myself again:
1) Call HH, and ask for appropriate booking code(s), fare class, etc., for an airline's award.
2) Call the airline (sometimes at a special number) and book the reward travel, putting it on a 30 day hold.
3) Call back to HH and request the cert. Take the cert to the airline and exchange for a ticket.
The important thing in your case is to realize that HH has the details, but doesn't know how to use them. Those details, though, in the hands of a good AC rep, will get you what you need.
So I suggest you call HH and write down exactly what they tell you. Then call AC and if the rep seems to stumble over the alphabet soup, just hang up and call back until you get a 25 year veteran CSR who will walk you through the whole process with aplomb.
Good Luck!