Would one need to worry about a JG roo mating with a normal sized hen because of the weight difference of the roo? Do you find your roo (who sounds awesome) to be a gentleman in that regard? I've only ever had 1 or 2 roos in all these years who were not total snots to the hens.
The idea of a roo that is twice a hen's size being mean to my hens is something I'm concerned about.
I think most roosters are rapists during their self education years. Then they mellow out.