For me, the event is over. I won't have another shot at legendary raids until next week some time, so I went ahead and raised my personal Ray.
I had 2 worth raising. 1 was 14/15/13, and the other... 15/10/13. The lower stat total on the later makes it worse, right? Well... I put these two in Pokebattler and found some odd results. The 14 atk was generally better, but the 10 df was never more than 1-2 seconds behind at lv40... This was also true when compared to a 100%. In fact, there were several raids where the 10 df ray had better clear-times than both the 14 atk and the 100% that I tested against. And yes, I understand that this is due to higher energy gains.
So I went with the 15/10/13. TRIED to change its moveset, but ended on dual flying every time. Meh, still raised it to 33.5 with a goal of 37 for Machamp breakpoints.
Well, today a Machamp raid appeared with Counter/HS. Before this guy I had no real chance. But with him, I figured I'd try. Led with my Gardevoir and did solid dmg, then in comes Rayquaza.
....he only lasted like 10 seconds, but those seconds were glorious. Thanks to its minimum defense, this thing spat out a constant torrent of arial aces and ate like 1/4 of the Machamp's life away. Seriously, I only had to airslash like 3x because just taking counters and dodging heavy slams was enough to keep it charged. I took it with 35 seconds on the clock.
In short: I took a subpar Rayquaza and have a subpar moveset on it (which I might keep for a while as I like being able to take EVERY Machamp variant now), and found something beautiful. Seriously, dodging around and spitting out arial aces left and right was the most fun that I've had at a raid so far =P