The 12" circular needles aren't too short for socks on 2 circulars, but they are waaay too short for magic loop. If you want to knit socks on the two 12", go right ahead, but I would recommend at least a 16" cable. I use a 24" and they're just right. For Magic Loop, use a 40" or longer. If you use Addis or Options, you can get by with a 32" needle.