Gene51 wrote:
Arca Z1, Markins M20, RRS BH55, Kirk BH1 - are all heads you should be considering. Keep in mind that with a Sidekick, the ball head is subjected to lots of torsional forces and the connection between the stem and the clamp must be absolutely up to the task of being used with a Sidekick. Some of the lesser ballheads are not recommended for Sidekick use.
Gene51, do you know offhand whether the RRS BH-40 will work with the Sidekick as well? I found this link that provided compatibility with the Sidekick, and the BH-40 was not listed under the mid sized category.
Just curious. I will call them to check on it regardless.