New Roommates - Kitten and Cat

I am in a frustrating position and Iâ€[emoji]8482[/emoji]m not sure Iâ€[emoji]8482[/emoji]m going to find an exact match to my long and complicated story on this board, so Iâ€[emoji]8482[/emoji]m going to try to post my own.
I have a three-year-old cat named Gizmo (fixed, declawed in front), and sheâ€[emoji]8482[/emoji]s always been an extremely playful cat. She will play with anything – a resting hand, her own tail, a plastic bag, even things that arenâ€[emoji]8482[/emoji]t there. Granted sheâ€[emoji]8482[/emoji]s calmed a little with age, but Iâ€[emoji]8482[/emoji]ve always wanted to get a second cat so that sheâ€[emoji]8482[/emoji]d have someone else to play with.
Well, I recently moved in with a friend, and he just so happened to have a cat of his own, Emo, who will be a year old in June. Emo (also fixed and declawed in front) has had very little interaction with other animals, or people for that matter, but has apparently also been very playful, himself. For this reason, we thought that they would make good roommates as well.
When we moved in to our new place, we did what all of the advice says and introduced them gradually, letting each of them roam around and explore the place on his/her own. When they finally “metâ€, they had a little initial hesitation but quickly seemed to not mind each other.
However, a few days after that, once they both seemed to be getting comfortable, Emo began chasing Gizmo around the apartment, cornering her, and attacking her. It is not a huge place, so she doesnâ€[emoji]8482[/emoji]t have a lot of places to go to get away from him. Plus, he is about 15 pounds to her 6, so he clearly dominates any play-fight. Which, I think he thinks these little scuffles are. I realize heâ€[emoji]8482[/emoji]s still a kitten (albeit a large one), and just wants to play. Gizmo, on the other hand, is clearly caught off-guard by them and gets on her back (her defense mode, since she only has back claws.) and hisses, growls, screams (loudly, like her tail is being stepped on), etc. At first I thought he was hurting her, but I have closely inspected her on several occasions and she seems fine. I have read that these things cease eventually and to leave them alone, but the cat-fight-like sounds are getting to be too much to bear (and Iâ€[emoji]8482[/emoji]m waiting for the call from my neighbors…), so I have intervened a couple times. Since they are not actually violent cat fights, they are very easy to separate and Emo generally retreats before I even come near. I have tried “punishing†him for attacking her by spraying him with a water bottle, which works to scare him away, but is only a temporary fix. As soon as he spots her again, heâ€[emoji]8482[/emoji]s pouncing on her back.
I really donâ€[emoji]8482[/emoji]t think he has any animosity toward her and really just wants to play (he is often chirping at her curiously and looks for her constantly when sheâ€[emoji]8482[/emoji]s hiding, but the play is clearly too rough and frightening for Gizmo. Iâ€[emoji]8482[/emoji]m worried about her stress and the fact that she really doesnâ€[emoji]8482[/emoji]t get a chance to let out her normal playful side (with inanimate objects and me) because sheâ€[emoji]8482[/emoji]s always on the defensive. Itâ€[emoji]8482[/emoji]s obviously upsetting to me since my cat seems to be getting the brunt of it, and my roommate is rarely home (particularly at night, when he works, and Emo becomes especially aggressive, adding sleep-deprivation to my list of frustrations).
The weird thing is that they are not fighting all the time – usually when I get home from work, they are both sitting together peacefully in the windowsill. Minutes after I walk in, though, Iâ€[emoji]8482[/emoji]ll hear her shrieking from the kitchent. But then later, when Emo is calmed-down, they will fall asleep next to each other on the same bed. But those times seem few and far between…
Anyway, I know that this is an incredibly long story (and itâ€[emoji]8482[/emoji]s only been about 2 ½ weeks!), but I was hoping that if I provided as much detail as possible, someone out there might see a solution for us! My vet couldnâ€[emoji]8482[/emoji]t offer me any suggestions past what Iâ€[emoji]8482[/emoji]ve already done. Iâ€[emoji]8482[/emoji]m already starting to resent Emo, and donâ€[emoji]8482[/emoji]t want that to be the case. Thanks so much!

It seems to be a fact of life that a lot of male cats think it's their job to terrorize females and it gets worse about once a month (full moons - not my invention) but never goes away completely, and because of the size difference apart from anything else, I'd be very careful about leaving them alone together at any time. He may not have terrible intentions, but she can't tell the difference and it's unfair to put her in his path all the time. She needs a safe place to be and all the tricks in the world might not change him; certainly punishment never will, and Feliway might have a good effect but it's hard to predict how much for how long. If you can keep them in separate places when you're out, she'll feel a lot better and he'll just have to manage without his favorite toy.

Hello, we also have a little female and an extra-large male that fight like that. We decided they are ok. We're trying to teach the male not to play so rough. If you provide Gizmo with some little hiding places she can run to when she's getting chased, she should be ok. If they are sleeping together, they're probably friends. He just plays a little rough for her. Trying playing with him yourself, and chastise him if he starts biting to hard.