New cat in house and behavior problems

Question
We have an 11month old male who's lived with us sine he was 8 weeks old.  He's 12 pounds of loveable, well behaved cat, gentle and yet playful.
A week ago we purchased from an animal rescue a 2 year old 8 pound female.  She'd recently been spayed and had a litter 8-9 weeks ago.
Our male has been fine with her, no aggression at all, just tries to get her to lay by pouncing and batting at her in the cat like way.
She gets all hissy when he does that, slaps at him with claws out. (he has nom front claws)
Once she get hissy with him he withdraws and silks, get real leery of her and is actually submissive.  He'll be drinking, she comes over and he moves away.  Turns his head the other way as she walks by etc.
I meant play with her above, not lay.
Anyway, we have 30 days to decide if she'll work out.  Our vet todaybsaid her hormones are all crazy yet from birthing and then being spayed.  She's loving and gentle with us.
Do you think she may become more receptive to our guy or should we have gotten a kitten for him instead?  If she will only tolerate him and he' s not happy with her shunning him, should we return her?

Answer
I have found that eventually most cats, when having gotten to know each other, give each other their own "space" for the most part. While there still may be the occasional incident of a bat or two, which you can treat with the water spray bottle method on the aggressor, all should be well when the cats get used to each other and your new cats' hormones are back to normal.

I have never given up a cat once I took it home. There are always times when cats suddenly take swats at each other, but they are few and far between and every cat eventually has accepted the new one, given time and equal love from us humans.

Good luck to you!