How are you planning to sync the flash with your Crown Graphic? Do you have a shutter with a flash sync built in, or do you have a synchronizer? What type of shutter or synchronizer do you have?
The problem with using a flash with a Crown Graphic is you have to figure out some way of getting the flash and shutter to talk to each other, and then you have to get them in sync with each other. After that, you have to calculate how much shutter speed and aperture you need for your flash setup. All of this can be done, but it all takes a bit of work and research. First figure out how your shutter wants to communicate with the flash gun. Then figure out what kind of flash gun you want. Then figure out what kind of cable you need to connect the two. After you've got all of that figured out, then you're ready to buy. Be careful though. You may find that you have the right flash gun and shutter, but you can't find a reasonably priced cable to connect the two. All of this stuff is old technology, so sometimes that little stuff can be expensive.
I'm not sure that the Kodak Flashholder would be a good choice as it isn't designed to work with large format cameras. I'm sure it could be adapted to work, but it may be a bit more work.