I prefer to go at night too. Sometimes girls haven’t seen anyone else during the day and they’re charged up later. Sometimes they’ve cum twice and all they can muster is a half a boner and a drop of cum after furious jacking off.  
You can always tell a girl what you want and ask her what time works best for her. I usually set up appointments early enough that I can ask a girl if she’ll have energy later. I have a cadre of regulars who are pretty good about accommodating me. I got into the position of having that by talking to the girls.  
Frankly, just being open about what you want with a provider is something I think most guys don’t do. You’ll get a lot better information asking your provider this question that asking a bunch of guys on a forum.

I've had visits first thing in the morning and visits late at night.  

I've noticed that when I might be the first customer of the day, they may not cum so they could save themselves for the remainder of clients during the day. I've noticed a lot of my earlier appointments will usually end in somewhat of a rush like 30 minutes and they start aggressively jacking you off.  

I've had a few very notable late night visits where we go over the hour and they're still going. The visits where I end up with a large nut in my face is usually at later night visits.

Depends. Usually Fridays, Saturdays & Sundays are busy between 9PM - 2AM. When I first started doing sessions weekend nights are the only times I saw Tgirls & I got a lot of rush jobs. But it depends because if they haven't seen anyone & you catch in the night the tend to be hornier lol.  

Now I see girls in afternoon between 1PM - 5PM. Sessions have been better on average. Nights have been good too. I usually go Monday - Thursday around 8PM - 12AM. I don't go too late like 2 - 5AM, that's probably the worst time to go.