Yeah you have to have perfect timing and teamwork if you're doing it at 290. If you can get up to 294/5 it gets a lot easier. I spent at least 10 hours(split between 2 days) trying to teach people Oryx. I wanted to get it done before the reset so I joined one of those "elitist" 294 or higher with 290+ snipers only groups and we were able to do it in an hour. With the lower levels we had trouble staggering him with all 6 + weapons of light. With the higher level group we successfully staggered him with 2 people down.