They don't hire onto A330. For A320, the schedule is like this. Month one, 5 days off, month two, 8 consecutive days off plus and extra 3. Therefore 16 days off over two months.
More of the good layovers are going to a330 or 767/777. Still, there are a few nice stops in Saipan, Phnom Penh, Ho Chi Minh, etc, etc.
For A320, there is quite a lot of domestic flights. Depending on various circumstances....it could be between 20-75% of your monthly schedule.
Any specific questions, please feel free to ask.