Boy or Girl?

For most of my greyhound research and planning, I've been leaning towards adopting a female.  This is because:

-They tend to be smaller
-They don't mark as much inside (Niles can be a pain that way sometimes)
-I read that they tend to be more independent (?)
-Niles is a male, and while he's not really met any dog he can't get along with, he seems to have more tolerance with the girls.
-The sweater I've been knitting will probably not fit an average male.

       Size is kind of a factor.  I'm used to the Labrador size, being around 50-70 lbs, but the smaller the better (without the dog being an Iggy).  Especially since a main difference is height between the boys and girls, that I can tell anyway.  Additionally, there are more apartments that allow dogs that can maaaaybe pass for 50lbs.  But we'll see.
        The marking thing is something, that while I know is not a trait of all males, I would ultimately like to avoid at all costs.  Whenever we travel, Niles tends to have the urge to lift his left repeatedly in hotel rooms and while walking if allowed, which I find exceedingly annoying.  He also had some troubles a few months back where he would pee on the couch for unknown reasons while unattended, and also walks in his pee pretty much every day after lifting his leg.  While extreme due to his size and fur, etc., all of these things make me want to just skip the possibility altogether.  I want to be able to take her wherever I want without having to worry about such matters, ultimately.
         I wish I could find the site, but I read a greyhound rescue that had a FAQ section that said boys are more clingy and affectionate and docile, while the girls are more independent and sassy.  While I'm looking for a mellow, easy going dog, I also need one that is comfortable being on her own, should I have class or work for six hours at a time.  Hopefully a girl like this exists for me (perhaps minus the sass).
         As for greyhound gender specifics, I don't really know that much in truth, as my experience with different sexes in greyhounds is pretty limited.  If any of my greyhound superiors have any comments they'd like to leave about this, I'd appreciate it ^_^.

Below are the dogs at the greyt expectations greyhound rescue that might work for me, should they still be around in another month.  There's even a red-head, which I've found I'm kinda partial to:

Hush Tidal Wave
Darla
Cutter

Just another "in waiting" greyhound entry.