Re: is it worth even trying?
Personally, I think unless your body is already heading that direction on its own, it's all just extra work (and mental stress) for you. I think of it like a giant glacier slowly melting and moving. I can blow a hair dryer at it right as it is breaking free and conclude that the hair dryer helped it move along. Or I can do it a week before it breaks free and conclude it didn't do anything to help.
On another note, I figure that optimal positioning is important for a smooth labor, especially if size is a concern, so I wouldn't want to do anything to override my body's response (waiting) for better positioning.
Melissa-Wife, mother to DS 4/02 and DD 4/07, DS 7/08
ISO: my lost shaker of salt