I’ve had a wonderful top-of-the line Bernina for 15 years and I had never purchased a narrow hemming foot! The problem with narrow hemming the other way (turning and stitching, trimming and turning and stitching again) is that by the time you stitch around the hem twice on delicate fabric, it almost always starts to flutter.
Here is a narrow hem technique I saw on a very expensive designer silk skirt (Project MyWay #1): The skirt front was narrow hemmed, the skirt back was narrow hemmed, then the side seams were sewn. If you’re careful to have the side seams of the fronts and backs end at exactly the same place, this gets around the fact that the first half inch in of a hem using a narrow hemming foot looks horrible, as it’s hidden in the side seam.
Here is the best tutorial I’ve found for narrow hemming from Jan Andrea, at Home on the Web., it has great pictures and instructions:
Even with this great tutorial, I was still having trouble catching my stitching on the folded hem. Finally, I changed from my single hole sole plate (which I always use on fine fabrics–keeps the fabric from getting shoved down into the throat plate) to the zig-zag throat plate and set my needle position to the right. This worked pretty well for light weight fabric.