For a show I'm designing now, I have two S4s mounted on wooden bases which are being used as roving shins, one per side of the stage. Each unit has two or three different focuses throughout the show, and the units can't be moved into place until just before they're needed to stay out of the way of actors and scenery. I have the base locations drawn out on the floor for every focus the units need to be placed in, but I can't figure out how to notate the shutter cuts. How can I accurately mark the shutters such that I can preset the shutters before the unit comes up without seeing the light?