All (relevant) slits can be found from the home screens in the "Beamline" tab. The screens look like:
<inter screen grab>
The screen shows the slit with gap & offset motion. The four motors are shown below.
They are also available from the <hutch>3 hutch-python interface. Detailed documentation is here.
A brief list of available commands are:
<slit>(): return opening
<slit>(new_size[,new_size_b]): opens to new_size (or new_size and new_size_b)