You can get as many kills as you want to in WCP and SO. You just need to have the patience, fuel and decoys. Just fly the second mission of WCP where you have to rescue Maniac and the Redback squad and instead of following the nav point route after locating the Panthers, fly through the middle: meet a carrier and a wing of Morays. Take out the Morays, auto pilot to the Midway, fly out there again to meet the carrier and a fresh wing of Morays. You fail the mission, but come out with a stack of kills anyway.
Just be wary of which missions you decide to do this on, as some missions will give whatever kill score you manage to Stiletto as well...And you can't have her topping the kill board