This is my first time building a level 10 gym (we are not spoofers) with my family, so I want to share to you guys.
Pokémon ordered by their CP.
It all starts with a level 3 Valor gym with Vaporeon/Snorlax/Snorlax.
Then, we took it down, and had placed Kabutops/Raichu/Vaporeon.
We prestiged it up a little bit, then some Pokémon were added, the most noticeably, Venusaur, which CP was between Kabutops and Raichu.
Note: we had prestiged with Kabutops/Venusaur/Raichu the most overall.
The gym went up to level 8, 9, and then 10!
The final 10 Pokémon: Kabutops/Venusaur/Raichu/Vaporeon/Arcanine/Arcanine/Snorlax/Rhydon/Gyarados/Dragonite.
But when I was testing how strong I was, someone, possibly a spoofer, maybe with some of his/her friends and likely, all were Valor players, started taking the gym down. I wasn't sure if they were the players who were at the gym before our taken down.
I finally finished the test, I was only able to beat 7 Pokémon; meanwhile, possibly, the Valor players are very strong. The gym would have gotten to level 8, but we kept it at level 9. Then, we couldn't defend the gym anymore. The gym was filled with 3 Dragonites, by Valor trainers.
Strangely, I only saw a few people near the gym, and most of them didn't seem like playing Pokémon GO. So, are the Valor players spoofers or normal players? Everyone except for themselves won't know, even Niantic.
Building level 10 gyms and looking at it to be taken down is pretty funny.