The dots behind her belly are most likely the fry's eyes. The gravid spot refers to the whole dark patch there. If you can see eyes of fry, then she should have more soon, as the fry are pretty well developed. Can you tell if it's eyes or not?
It's hard for anyone to predict how pregnant someone else's fish is, because they just vary. Some get hugely fat, and some barely do. One of my females barely gets past a little fat, and then she has her fry. She only has a couple per batch, but it's every month. So it's impossible to say how far along someone else's fish is, very accurately, because they all differ.
Okay, as long as she doesn't look or seem stressed, she should be okay. I wouldn't recommend you keep her in there more then 2-3 days though, because after that is when it can get very stressful. Your breeding tank sounds pretty good. Maybe next batch you can put her in there for the birth.

One of the best ways to get hiding places for the fry, is floating plants. Hornwort is especially good. But any dense ones are great hiding places for fry. You can pretty much be assured you'll get some fry if you have floating plants.
