In April I'll have a chance to fly my first long-haul since becoming A3*G in 2015: London to Shanghai to Athens in economy.

How do I go about finding the best solution in terms of earning miles without jeopardising in comfort? I mean the obvious choice for the LON>SHA would be a non stop BA which I will need to replace most likely with a 1 stop LH but then they only give 50% for basic economy? On the other hand I'd rather fly a LH A380 than CA.