I did it where I could by using a 5mm piece of ply between pistons so they would in theory pump out with brake pedal and most of the job would be done.
I didn't however go like that, as soime were seriously siezed, and I had to use a internal expanding grip to spin them at the same time as applying a slight upwards force.
It took me say 30mins to get 5 out, then to get other three out took a full day, just working back and forth.
tabetha