I've just recently had a new Lucky Friend after battling together in Gym. We then decided to go for the Rayquaza trade. As neither of us had a Lucky Rayquaza yet, and it could potentially have the chance of being really good IV thanks to the minimum of 10 IV in each stat. I do already have a 98% IV Rayquaza from the last time Rayquaza was a Raid Boss. But still, gotta try to aim for that 100%, or another 98 that has 15 attack instead of 14 like mine. So since it's the current Raid Boss I opted for getting that one, and so did they. Then we traded a Rayquaza we had in our storage.
I got this Rayquaza out of that Lucky Trade. Its IV is not particularly outstanding, but it's great to have another Legendary as Lucky. Perhaps the next Lucky Rayquaza will be better! The chance of improving my best Rayquaza is super slim anyway so I wasn't expecting it due to the amount of possibilities. I still Bayleef I'll eventually come across a 100% :D