Thanks Calchas

I dont have any tiers on BA, AA, CX or any other one world carrier.

Have enough CX miles on MPO, but got them from credit card spending so hence no status. Do lots ot intra europe flights where CX Asia miles not get the best priority for availability so thought would throw some flights in the BA Avios program and take AA challenge to get Sapphire tier status quickly and the balance collect on CX Asia miles.

But do you think it would be better to go up tiers in CX, BA or use the AA challenge in my case?

Thanks again