*It's easier than the directions would have you to think.
*I wouldn't use less than a 29" length circular needle, size is irrelevant, that would depend on what you want your stitches to look like.
*If you can tough out establishing your Moebius and knitting the first round then you've got it made.
*A marker between the first and last stitch is ESSENTIAL, otherwise you would not know where the beginning/ending of your round is.
One of the sites I looked at about this said that it was easier than it would appear and that's right, it's just a bit difficult to knit with your circular doubled over on itself as if it was still in the package. Once you get past this then the rest is easy, you just knit your pattern (whatever it is) until it's the width you want it to be then end it.
You just have to pick up your needles and start knitting, not letting the first couple of rounds frustrate you. I would not recommend a beginner knitter try this until they get more experience under their belt.