Saddles might help, but if he is breeding them so far without incident or injury I'd just keep an eye on the situation for now. As Ridgerunner stated, with living animals you can never predict for sure what's going to happen.
As you can see from the other posts here, it's not so much the size...
From my experience it's not the weight of a cockerel/rooster that's an issue. It's that a lot of these big guys are ungainly and when they get up on the hens they can't maintain their footing. They keep sliding off the sides, which makes them try to hold on tighter. I've unfortunately had a few...