This is a cowardly answer, but I might as well share. For days where the daily token is attached to a mission, here's what you do in customs:
>1v1
>Simple Battle
>Map: Ground - Port Base/ Space - Space Fortress Interior
>Whatever MS cost you can get a single easy kill with. Stealth Preferred.

Start the match, blitz the opposing single enemy and then run/hide for the rest of the match. Remember to me still/crouch between enemy spawns to heal any opposing damage. Keep ratings low to lure in unsuspecting players.