Hugill sang the songs as work songs, but he did not have much of a voice imo, yes lighter you are correct in that respect he sang them well enough, but their purpose in folk clubs is to be as an audience participation happening.
singing it as rio or reeo hardly matters, the argument for singing reeo because the blessed Stan sang it that way is weak, if he sang "nigger" that is not a reason for singing it.
Stan was very knowledgeable about shanties, however,i understand his politics were reactionary