The stingers will give you better penetration, the spitfires will make a larger wound channel. I don't know the specifics of your setup, and whithout them I can't recommend the spitfires. I will say that to shoot he spitfires you should have at least 60 ft/lbs of Ke to insure good penetration. The magnus stinger 4 blade would be a good alternitive to both. It' penetrates well, cuts a good size hole, and shoots the same as the two blade heads.