As a QLDer, IMO you want to keep Inglis up against Roberts, he’s a f**king pot plant in D at times. So this is what I would do.
Morgan to 1 for the first 20-25 mins and carry Ponga on the bench. I have concerns that Maguire will be short on a run after missing the last 6 weeks and will need a breather at some stage in the first half, slide Morgan into 13 and bring Ponga off the bench to 1. Up against a tired defence Ponga could be electric and doing it this way you avoid throwing him to the wolves for the ‘softening up period’.
Morgan is a bit more robust in size and can handle the opening shit at fullback IMO, I reckon Ponga would get hosed playing fullback straight up by the blues.