Originally Posted by
spherehopper
I've just booked a DONE4 and thought hard about where to credit the points. I originally thought Matt's idea best but as AY requires 80k for Emerald vs BA Gold at 20k. Best earning rates away from the host airline is going to be, for BA, 50% (EI, AY, JL, QR etc) so 40k miles needed (hiding fare from AA/BA by using codeshares on their legs). Best rate on Finnair is 250% on the "FAIB4" so 32k miles needed.
Actually it's not 32k for AY+ because of the elite tier bonus that you eventually get as you attain different status levels.
If you are starting from 0, it's roughly 30k on the 250% partners and 25.6k to retain platinum. That's all without converting avios to tier points 3:1.
Also, the BA bonus tier points is a temporary promotion at the moment... Without any guarantee of extension.
In the end,it really depends on where you want to go..but the key is marketing carrier codes. Also, a minor detail but I would not get too focused on "hiding the revenue from airlines" as that assumption can lead to incorrect conclusions about other things.