My solution to a similar situation is to fly US, UA, CO as much as possible and credit everything to Asiana. After you hit 40,000 miles in 2 years you will be *G and have access to all *A lounges and will board early in the process so you can get a place for your rollaboard. You won't get upgrades, but I don't need them because 90% of the flights I take are on RJs without first class. Also get the Aisana amex from B of A which gets you 2 miles per $ of spend.