you know, i've cast on circs and thought i had all the "bumps" facing center, but because I was knitting on big needles, they'd actually twisted without my realizing it (i suppose because the loops of yarn were so big and the circ cord so thin). it was really difficult to tell. so i corrected myself by trying to control as much of the cast-on part as I could with my hand and arm, squishing it and holding it so it couldn't twist until it was time to join, at which point i spread it out carefully along the cord to the needle. does that make sense?
I think so. Before I join on a circular needle, I go around the cable and make sure all the stitches are going the same direction, spreading them out a little so I can see them better. Then when I get to the end, I make the joining stitch quickly so they don't have a chance to get twisted.