I was thinking along the lines of getting a RRS Arca-swiss L-bracket, and getting a head to match, I was wondering if it would just clip into something like the 357/501/504 slidy-plates. (I like the idea of the slidy plates because it's less to shell out on a real macro-rail or for panoramae-positioning, even if it's not as easy to use).
Do arca-swiss plates slide, or are they just clipped in and held fast in all directions?