You don't
It's a challenge. I end up going for a native wide angle lens with the best autofocus possible.
Every now and then I'll reach around and pull focus but most of the time you have to rely on autofocus.
They sell some attachments to pull focus but I haven't gotten them yet.
I'm going to order the servo set up for the crane 3 and try it out.
For the GH5 speedbooster and sigma lens combo I use you pretty much have to shoot in manual mode so I end up not being able to use my best set up when I'm running the crane.