Hi and welcome! I couldn't get your link to work but here's one
that shows the machine. I don't have the machine but you could just try both methods yourself and see how it goes. The advantage of trying it out is that you'll be making a gauge swatch at the same time. That'll give you an idea of how many stitches per inch your yarn gives and then you can figure out how many sts to cast on for whatever width scarf. Watch out for curling edges
on the scarf if you work back and forth, however. One of the advantages of knitting a tube is that you avoid this problem.