I know you want to start your trip in ATL but I just want to share with you how I redeem my miles. I got this idea from reading the post on FT.

I redeem 80K BA mile on 2 rountrip tickets to Easter Island with stop over in Santiago, Chile on LAN at the end of October. This is the best use of mile for us because we live in Los Angeles. We paid $140 for tax for 2 tickets. I check on LAN website the same ticket cost about $2000. We always want to visit Chile, so this is work perfect for us but I will never think about adding Easter Island to this trip without have to pay any additional charge.

Redeem your mile for Europe is very expensive because of the BA fuel surcharge.

Some people suggest to redeem the mile to Asia because BA allow you to stop over. You can visit many countries in one trip. You have to pay the fuel surcharge too on the partners airline but at least it might be cheaper than BA fuel surcharge. It cost 50K to Asia. One time I call and check for LAX-NRT-BKK round trip. It cost about $300 on the tax and fee.