From my limited experience (I successfully snagged 3 *A coach TA awards for next summer's travel using US miles), I can make a few suggestions.

First of all, for the dates I was looking at, AC had the best TA availability (better than US, LH, or LX); both my outbound and return TA segments are on AC.

I needed 50K miles per ticket (not 60K for *A). According to the Website today, it's still 50K miles.

So I recommend this:

• Because you have enough miles for one ticket now, get that AC ticket now
• When the needed additional 15K miles have posted in ~1 month, go back and get the other AC ticket. I personally believe it will be available.

I understand what you're saying about transferring some miles around and getting the second award ticket directly from AC Aeroplan, and sooner. Before you do that, I recommend you investigate (including the FT board for AC) the taxes/fees you'd need to pay AC. AFAIK it's pretty steep. (For comparison, taxes/fees payable to US for the all-*A itineraries were a bit less than USD100/ticket.)

Hope this is helpful - good luck.