Maybe it’s just me but I always found that flash brackets didn’t offer me the quality I was looking for for the trouble they were. Anyway, all the weddings I shot with my mentor Jenny we used large studio strobes off camera bouncing into umbrellas for reception halls. All flashes were triggered by radios. Bouncing off ceiling or direct umbrellas depended on ceiling height. Something to consider next event that isn’t critical where you can try. You can start with a shoot through umbrella on an adapter with a speedlight on a monopod. For receptions go for just direct speedlight. You can have an assistant who knows flash and sets the power, or set it at about quarter power and figure out the distance you need, telling your assistant to always remain that far from what you shoot at a 90 degree angle. Optionally, you can also use a TTL capable commander and see what it can do. It often works nicely. Just from experience, Nikon’s TTL worked better than Canon’s when off camera in the past, but I’m sure this has changed so nobody take that to be a certain thing — just my opinion and was largely the reason I chose Nikon when originally going for my camera.