Usually 10 days is plenty, if she had tapered off a good amt before she is separated completely from then, even 7 days is fine. She won't be fully dried up but enough for the spaying.
If they nurse up until she is separated and still full with milk then 10 days is okay.
I'd say put them up for adoption at around 10 weeks. They won't all get adopted right away so some of them will get a little bit longer with mum. The longer they stay with her the better, but the younger and cuter they are the easier it is to find homes for them.
Ask whoever adopts them to sign a contract promising to get the kitten neutered or spayed, vaccinated and promising not to have them declawed. You should also ask them to return the kitten to you if they can't keep them for any reason. That way you know they won't end up in a shelter, or worse.
Ask the new owners to pay an adopting fee. Kittens given away for free sometimes suffer a terrible fate, if whoever takes your kittens has to pay a fee for them and sign a contract they'll stand a better chance of going to good, loving homes.