Cat experts please, I'm introducing a new kitten?

[ubernerd122]

This is a bit lengthy, but please read it over and give me some tips.

I'm introducing an 8 week old kitten to my four year old cat. The existing cat hasn't been around other cats since she was a kitten, but exhibits strong motherly tendencies (she treats her toy mice like babies). She's very territorial when it comes to people she doesn't know in the house, especially women.

The new kitten is very mellow and laid back, and a male. I've already designated the safe room to be my bedroom so that the existing cat can retain the rest of the house as her territory. I let them see each other, but they weren't allowed to get close yet. The existing cat was very wary but didn't appear to be aggressive. She only growled lowly but didn't make any offensive body language. I also let her smell the area the new male was exploring to get used to his scent.

My question is, about how long do you estimate it should be before I let them have a face-to-face encounter where they can do their usual posturing and such?