I've been submitting some stockings sites, and I usually go with this order:
1. stockings (obviously

)
2. lingerie
3. legs
4. pantyhose
5. fetish if there is absolutely nothing else.
I try to stay away from feet as that is a pretty particular niche, unless it really is a foot fetish site. I don't really like pantyhose either, cuz to me pantyhose have a crotch (to be a bit crude lol) and stockings are usually thigh high - I notice that most of my sponsors separate stockings and pantyhose a lot of the time.
My advice would be to look at the listings in each LL that you are not sure of and see where most webmasters put their stockings sites. Takes a bit longer, but gets you in the right place.
just my experience, hope it helps.
Ponygirl
edit: ps - also it depends on what site you are promoting for your sponsor, is it a stockings site, or a leg/pantyhose site?