Every node in the game has a 33% drop rate on character shards except the ones that don't have character shards at all, where it's of course 0%. Gear drop rates depend on what the energy cost of the lowest missions with that gear are. The lower gear drops at a higher rate. Cantina missions tell you how much cantina currency each mission gives you, and that does increase for the higher energy. If allyou want is that, you can calculate which nodes are best. I did it once and can't remember what it turned up, because it's rare that that's what I care most about. (It mattered to get characters from cantina shop in time for Thrawn, so I was making calculations then.) Most of the time the thing I most want from cantina missions is character shards, so I do the lowest energy cost missions I can for the character I'm working on, because it doesn't make sense to pay more energy to get the same shards.
