I have the exact same problem. I'm using a 77mm B&W SLIM CPL, on step up rings connecting the filter to lens with diameters of 52mm or 67mm. the SLIM CPL doesn't have threads on its front (which makes things even more complicated) I have a 77mm collapsible rubber hood that's blocking part of the frame (on all of its collapsible states) when shooting with a 28mm FX lens. which "wider" lens hood would you suggest? could that hood be fitted straight on the step up rings? Cheers!