No problem. Keep in mind that that is the maximum litter size, she could easily have less nymphs. However, whatever the litter size, it should be much more than many other genera!
Well Gyna bisannulata and G.capucina need a chunky, well aeriated substrate, which you should keep moist. They like it warm, 80-85 Fahrenheit. Fruit should always be available, they don't seem to reproduce much without it. On top of that all, make sure they are well ventilated.