The situation is that myself and several friends are going around trying to capture some gyms. Some gyms are already on our team so we train them up in order for us all to be able to place our Pokemon at the gym. Since we are a group we have the option for one of us to put in a Pokemon that we can use to train against (and leave after defeating that first one).
Is it better to put in a low CP Pokemon at around 20 CP for us to defeat using 10 CP Pokemon for the maximum prestige gain or is it easier to defeat a 1200 CP with a 600 CP?