Verified answer

How is the original hem done? In a factory with a hem stitch machine - not a delicate operation.

Use a serger to cut and finish the cut edge. Turn and single stitch with the sewing machine using a roller foot.

You may not have the same equipment the manufacturer had. When I am working with a knit of this nature, I take some steps to make hemming successful. I do pro alterations, so I do my best to make the new hem resemble the original from the outside, at least. This is your own garment, so do what you think will look nice. Once you determine the finished length, mark your hem allowance and cut away the excess. Using a ballpoint/stretch needle (probably a 75/11 Schmetz) run a machine baste stitch 1/4" away from your cut edge. This serves as a stabilizing stitch to manage the wonka-wonka stretch factor while you proceed. Then do what seems right to create the hem finish you want: turn and turn again and topstitch, serge and topstitch, blind hem. You can remove the basting once you are finished.

Be patient and pin carefully. You can actually hold the pins as you approach them to keep the fabric from stretching more. It may be useful to ease the pressure to prevent more stretching that causes ripples. Press well when you are done.

Sewing With Rayon

Depending on how the skirt is constructed, it may be easier to remove the waistband, cut off the excess at the top, and reinstall the waistband than to re-hem.

My first pass at hemming what I think you've got would probably be a serger rolled hem, but chances are the factory hem in the garment was chosen as the sanest option for the fabric and design, so I'd just repeat it if at all possible.

Never use a dull needle. It will never sew right. You need a ball point needle for this. Doll clothes this size are a pain in the neck to sew. Before your fist stitch hold the "tails" behind the needle from the upper thread and bobbin, take you first stitch and hold on to them as you sew, gently pull the fabric along. The problem is your feeder teeth underneath don't have enough fabric to hold on to, so it jams up.

I love long skirts, probably because alot of folks like short ones. Not that a nice set of legs isnt nice to see, I simply have always prefered just a little mystery

I like both. But so long as the person is comfortable using it, that's all that counts.