Originally posted by Just1MoreDave Maximize your flash power and minimize the ambient light contribution.
I would try this: Shutter speed should be at 1/180, ISO at 100, flash set to full power, control exposure by using aperture. If that's still not enough flash power, I would use an M lens to disable the P-TTL preflash, and add more flashes with optical slave sensors.
It might not work but it would be a hell of a show!
Its actually the opposite
you actually dont want a full power flash.
You need to lower your flash duration, so set it to 1/4 or less power.
The lower you drop the power the faster the strobe and the more stop motion you will get since the MINIMUM power creates the shortest flash duration and thats what you need.