Take a good look at his foot. Compare how many spurs he has, how big, and how sharp that spur is. Then look at those daggers on the end of his toes. How many toes and how sharp those claws are. When he is standing on the girl's back during mating, is he standing on his spurs or his claws? I think you are right, it is the claws, not the spurs.
He sounds more like a cockerel than a mature rooster. How old is he and how old are the girls? Cockerels maturing into roosters sometimes don't have the best of techniques. Most get better as they get older but "most" doesn't mean all.
You have different options.
Why do you want a rooster? The only reason you need one is if you want fertile eggs. Anything else is personal preference. Nothing wrong with personal preference, I have a few myself. Many of us would not consider having a flock without a rooster but it is an option.
Keep them separated for a while, a month or more maybe. Give him some time to mature. If the problem is his technique, maturity could solve your problem.
Some hens have "brittle feathers". If it is every hen it could be a nutrient deficiency in the feed but it could be the way her body absorbs and handles certain nutrients. A possible genetic defect. Even if the rooster is very gentle feathers break off and expose bare skin. I had a couple like that. When I ate them the problem went away. It's not always the boy's fault.
You can trim the sharp points off of the claws, same as the spurs. I use a dremel tool with that disc that cuts metal. Some people use a dremel or drill with a grinder head. Dog nail clippers can work. Like the spurs, the claws have a quick. If you cut too much off you can cut the quick and they bleed. They usually don't bleed much but you might want to have some flour or corn starch handy to toss on it to stop the bleeding. Usually if you only cut off about 1/4 of the length you miss the quick.
Do a search on hen saddles. These are capes you can buy or make to cover the back and sides to stop the damage. Do a search on the internet or on this forum.
I do not know what the correct answer is for you. If it were just feather loss I would not worry too much but yours are being cut. That's dangerous, I think you do need to do something.
Good luck!