One possible route to larger aircraft is working for Air Korea Flight Training Center. After a period of time you would transition to Korean as a first officer, or work in the corporate division. I don't know the full details, however, you can contact some contracting organizations such as Rishworth, Cambridge Communications, PARC, to name a few. You can google their web sites for phone numbers. They are very willing to take the time to talk to you.

Good luck