
'Female forks' usually come with a lighter spring than regular forks. Of course, in air forks, the 'spring' is the air chamber.
Usually, setting the air pressure according to your weight is all you need to do. Make sure you have something on the fork leg that can give you an idea of how much travel you are getting. If the fork doesn't come with an O ring for this, then you can use a zip tie. Go for a ride, and see how much travel you are getting from the fork. If the zip tie isn't getting pretty near the full amount of travel, then adjust the air pressure in the fork.
Rebound won't affect the spring rate. All rebound does is set how quickly the fork goes from being compressed to being extended.
HTH.