DD was a chronic catnapper - 45mins to the minute! I tried everything, including PU/PD to extend sleep cycles and nothing worked. I spent weeks sitting in her dark room, patting, shhhing, bouncing, rocking, PU/PDing... and nothing worked. I was SO much happier when I just went with the flow, even though I could tell DD was sometimes still tired, we were both better off.
To answer your original question, I found that the PU/PD method was the WORST for extending sleep cycles. It was far too stimulating and resulted in hysterical screaming. I would wake her up completely and then there was no chance of her ever going back to sleep. I did have some limited success with body rocking and rocking the bassinet - although very few times did it work. At most I'd get another 10mins of sleep.
I did do, however, a basic eat/play/sleep routine, although nothing structured to certain times, which I think works best for catnappers. I read every book and wish I hadn't wasted my time. I found the settling advice to be useful, however, and would always settle in cot after a feed, play and appropriate wake time. This worked wonders. By 4 months DD had herself in a basic 3 hour eat play sleep routine - eat, play, sleep after two hours of awake time, sleep for one hour.
There is light at the end of the tunnel though. At 5.5 months DD started to extended her sleeps on her own, through nothing that I did! She just slept longer one day, and has ever since! 1.5-2hours in the morning, 1-1.5 hrs in the afternoon - bliss! Just works with your LO and you'll both get to enjoy more of each other
Edited for spelling
This post has been edited by axiomae: 24/01/2013, 09:21 AM