Do you mind if I ask why an accurate measurement of BF% is so important to you??
Handheld measuring devices are not accurate, especially for those of athletic build and IIRC they are also less accurate for guesstimation of females, due to (ahem) breasts. Technically a woman with a larger bust may look much better at a higher BF due to the concentration of fat in more aesthetically pleasing locations.
I would say the best way of measurement is the mirror, unless you are going to be stepping on stage, or perhaps competing in a weight-class sport (eg boxing) where you want the maximum LBM-weight ratio.
Use the mirror and the scles to not as a way to approximate BF levels but as a general guide to get the 'look' you desire. Weigh and mirror first thing in the morning, then adjust diet and training routine accordingly.
Good luck.

Added on October 29, 2012, 2:55 pmDo you mind if I ask why an accurate measurement of BF% is so important to you??
Handheld measuring devices are not accurate, especially for those of athletic build and IIRC they are also less accurate for guesstimation of females, due to (ahem) breasts. Technically a woman with a larger bust may look much better at a higher BF due to the concentration of fat in more aesthetically pleasing locations.
I would say the best way of measurement is the mirror, unless you are going to be stepping on stage, or perhaps competing in a weight-class sport (eg boxing) where you want the maximum LBM-weight ratio.
Use the mirror and the scles to not as a way to approximate BF levels but as a general guide to get the 'look' you desire. Weigh and mirror first thing in the morning, then adjust diet and training routine accordingly.
Good luck.
This post has been edited by joeblows: Oct 29 2012, 02:55 PM