With MCC being how it is right now, it would be nice to have a wide selection of people to play some fun customs with. Add "Beyond Xander" and I'll add you back so hopefully there will always be someone to run an FFA or whatever with. Having up to 1000 friends is very convenient for this type of thing.
Sniper FFA's
this should help get you started:
http://www.thehaloforum.com/forum/halo-discussion/55-thf-mcc-gamertag-list