You can tell which ones are working for sure when their cityvibe add is indicating available for booking. Some others will also be working but not using that particular CV feature. The suggestion would be to call and see if they pick up. However, if you are not already established in the k-girl market they might not pick up or respond to texts and that would apply to any day of the week.
I've tried ones that are "available now" and other that are just listed normally. I have been established and screened by 3 different bookers, but no one seems to pick up the phone on sunday. I have no problem on the weekdays - but damn, another sunday gone.
And I was going to say text. It seems to be the best way for me. Oh well, everyone has their own techniques. I just checked CV and there are about 6 or 7 K-girls available. They're never in short supply.
Next time you hook up with booker(s) on a weekday, ask them if they have girls working Sundays. In case it's not already obvious - never block your number and always use the same number. It's generally not a problem hooking up on Sundays once you're well established, but a lot less to choose from. Maybe you're not cleared with outfits that work on Sundays. I seldom text and I call early.
The k-girls who work on Sundays tend to be the newer, less experienced ladies. Some of the 3-month wonders work 7 days a week. I don't know how they handle such a brutal schedule, but they do. Given that, I tend to reserve Sundays for trying out ladies with no reviews or very few reviews. (Only if they are handled by trusted bookers, of course.)
Sometimes you run across undiscovered gems that way, and they aren't yet jaded or sick of the job. They are trying to establish themselves in a very competitive market and so sometimes they will show you a better time than a lady who has been around for a while. Not always, but sometimes. Still, it's fun to try. Makes my heart pound a little harder when I arrive at the door, not sure of what I will see on the other side. It's kind of like throwing a Hail Mary pass. When it works, it's amazing!