Rex2008

Anyone advise me or tell me what's the best degree of camber to have on the rear of a 2008 hatch? It's already got natural camber but I need just a little bit more to tuck the wheel better in the rear arch, I'm running 245/40/18 rota grid drift wheels on a slammed wrx and it's tight in there! Would the whiteline rear camber kit sort me out? Cheers guys