Biphasic Sleeping Schedule - must sleep at same time each day?

[eveningninja]

I am interested in starting a Biphasic Sleeping Schedule. But before I do, I have a couple of questions...

1. I have school and work on different times each day, so I was wondering if it would be fine to take my core sleep (4.5 hours) and nap (90 minutes) at different times each day (whenever my schedule allows it).
-For example, one day I may have my core sleep from 3:30am-8:00am and then have my nap from 7:45pm-9:15pm.
-Another day my schedule may only allow me to do something like: Core sleep from 12:00am-4:30am and Nap from 6:30pm-7:45pm.

Would something like that work, or would I have to sleep at approximately the same time each day for the Biphasic Sleeping Schedule to even be effective?

2. Is it even worth it to try a Biphasic Sleeping Schedule rather than just a Monophasic? I personally think the idea of a Polyphasic would be awesome, but it would simply not work out with my life's schedule having to take so many naps.

Thanks.

[HenryJDaniels]

I'm also interested in the answer to the first question. Sorry if it's been posted before.