Firstly, are they seedlings or grafted ? Either way, moving very small trees into over large pots may not be wise, as the volume of pot mix may stay too damp without a good size plant to utilize some of the water. On the other hand you need to push the plants to gain size and produce leaves, which you will be removing ( frequently ?) for use in Thai cooking. I would pot them up in steps as they get bigger, rather than suddenly upsizing. Also housing them in a warm growing area and keeping up with fertilizing may allow a more continual growth pattern for leaf production.