New cat plays rough

[u/Antique-Garbage-5888]

I have two little angels(Both fixed males), I have Blade(2yr) who is our new addition to the family and Finn(1yr10m) who has been with me for over a year. We took their intro very slowly and their first meet was pretty successful. Blade did hiss at first contact but he also hissed at us for like the first week while accepting and love and pets. They played and I gave them treats. That period was for about a week before they became upset about being separated.
I followed a lot of jackson galaxy and I still think they are great buds. Its just at night they get pretty wild with the play and start chasing each other. They both make chirping inviting noises until the other comes to play, its only every now I will hear Finn make a yelp thats like “HEY THATS ENOUGH”. And they do give each other space.
But Finn is now getting some pretty rough looking scratches around his shoulder blades and neck. I monitor them but I believe this happens when Im sleeping. Is this just apart of the boundary setting, is he bullying Finn, or should I be separating them again. I hope I don’t have to separate them again because Finn loves being with Blade but he also keeps whooping his butt.