Setup 5 years billing cycle

Hi,

After looking for a while I found only parts of the answer.
I want to setup a 5 years billing cycle. From what I read the solution could be to use another cycle (e.g. triannually) make some display changes (easy language overrides) and add a hook to chnage due date.
Questions:
- Is there a better way to achieve this?
- Any hint for the hook to set up (where and what to do)?

Thanks,
Guillaume.