I bought a Kirk ballhead to hold my 500/501; it appears to be comparable to the RRS head. I love using that head for medium format and I do not think it was overkill at all. In fact, I think that when it comes to camera support, "too much is never enough." Why bother using a tripod if it is not rock-solid?
When I began shooting with a Tech III I found it too difficult to get the camera plumb, level, and square with a ballhead, so switched to a 3-way head for that camera.