Defender Movesets in 2 vs 1
Because damage taken affects how fast the charge energy fills, the best defending moveset in 1 vs 1 battle might not be the same in 2 vs 1. Correct?
I did some tinkering with qMike's spreadsheet and I might have got things wrong, but e.g., Vaporeon's Water Pulse, which is currently considered to be the best defending charge move for Vaporeon, would be the worst one in 2(+) vs 1.
Answers
Firstly, as long as the attacker benefits from type advantages and with decent dodging skill, the defender has almost no chance of winning unless the level differences is too big ( like more than half of the cp )
Secondly, for your concern, different defensive charge moves work on different attackers( players ), there is no one standard to tell which is better or worst
If you are so interested in defending gym, team up and train it to lv 10, then stay there and rise the prestige when being attack.