I recently failed to transition to biphasic sleeping over 14 days
Reasons for not suceeding: Not tired enough around nap-time, dispite cutting main sleep to 4.5 hours towards end.
Solution: I highly recommend being EXTREME about cutting your main sleep to start with until you ingraine nap time in. I will probably do 3 hours main sleep for the first 3-4 days next time.
Also I will cut caffine completely for the first few days - and probably invest in some ear-plugs for good measure. Noisy housemates at nap-time even though I told them
Solution: Moving in with ambitious self-dev enthusiasts in July
You can read my log here - Rags To Riches