The problem with ball heads, in general, is that after you tighten
them, they tend to sag. True, they don't sag much and sometimes it
is almost imperceptible, but sag they do. I have to try to place the
head again and again, compensating for the inevitable sag until I
get it right. This is not helpful. Therefore I use a geared head as
described in the next section.
I only use ball heads for fast-moving critter work, or for anything
with a moving target. Since most of my work is still work, in general,
I don't use ball heads at all. Instead I used a geared head as
described below.
[Swiss-Arca Cube C1 geared-head]
Geared Heads
For all my focus-stacking work and everything that does not
involved a moving target I exclusively use a geared tripod head,
specifically the Swiss-Arca Cube C1, with a knob quick-release