Any RaveOs experience that can help me?

Hi All – I'm relatively new to this. I've got 4 6GB cards mining Eth (converting to RVN) and I've got one 4G card I want to set mining RVN straight away. I can't get RaveOs to give me two workers or clusters with a split of my cards (4:1). It seems it can split over Nvidia and AMD, but not among the same manufacturer. Am I missing something, or pushing further than RaveOs can support?