Okay, so I'm actually a little confused about how a stud chain is used. I'm not going to use one, I'm just curious, because I've never used one, or seen one used. I'd hate to end up doing stud work and then be told I need to use one and I don't know how. The racing stable I worked at always used anti-rearing bits with a halter - all the colts had to be led in one, otherwise it was at your own discretion whether you could control a horse in a halter or not.
Speaking of which, do you prefer one over the other? I've seen photos of chains used different ways, including through the mouth. The anti-rearing bits just had a ring in the same place as the halter ring, so you'd clip them together with the lead.
Some reference images, in case you don't know quite what I'm talking about.
Chain through the mouth.
Anti-rearing bit (sometimes with a head strap instead of clips).
Under chin, from the cheek.
Over the nose. Most common arrangement?