If you have to put them in the net don't put more than one fish in a net and put some plants in the net too- make sure it isn't directly under the tank lights(if so move it or put somthing on top to shade it) but place it where it has a good flow from the current.
If the fish hasn't given birth after 4days put her back in the main tank for a day- it is a wise idea to try and keep track on roughly how long a female has been pregnant for as you don't want her in the net for more than one day.
Alternativly if you don't mind losing some of your fry to other fish in the tank(you may lose virtually all or none at all- it depends on the other fish in the tank and how hungry they are when the female gives birth) just let the female give birth in the main tank.
In my opinion both methods(breeding nets and free tank birth) are just as stressful as each other for the pregnant fish as although in a breeding net she won't be harrassed by other fish the lack of space can be stressful and vice versa for giving birth in the main tank.
If you go for letting her give birth in the main tank make sure it is heavily planted with plants that have little leaves(fry can hide between them better) and other hiding places where adult fish can't get to.
To try and incourage your female to give birth try to maintain top quality water conditions and set the temp at around 25/26 degrees, you will know when she is ready because she will start spending more and more time on her own and she will look like she is about to pop.
