Really 6 Flashes? All bigger than the hummingbirds themselves...they must feel like big champs in your garden I bet you could simulate football-stadium lighting with them. They will probably work even harder to get in the picture. Those are going to be big shots.
Good luck. I don't know how to technically set it up, but if you're finished, I'd love to see the result

Ps: You might need a "always wear eye-protection" sign at your door to avoid photokeratitis