User blog:DeadpoolN7/N7 characters on multiplayer

Hey guys, I've recently started to play ME3 multiplayer on xbox 360. I have all the packs that have been released and I've been trying to unlock some of the N7 characters. I'd really like to unlock the n7 slayer or n7 shadow but each time I earn enough credits to get a spectre pack I seem to only get guns or other loadouts. Is there some way to boost my chances to get characters? Should I be playing only on gold and just ignoring silver and bronze? Just curious if you guys found out any ways that might be helpful in actually getting new characters over just weapons and mods.