I'm curious as to what satellite has circular C-Band that you want to get? I see no circular C-Band from here and didn't think there was much at all unless you were in the east coast area. I have not seen an ortho like yours set for circular reception but I have seen a Bullseye II feed set up for circular and the slab in that feed is set just like yours at a 45° angle to the H & V polarities.