I don't think you need to save the fry. They aren't known good hiders for nothing.
Livebearers are quite prolific. Let alone a female producing several batches of fry in a few months without a male after being separated from the male(if separation is being done). Inbreeding is also quite common in their case. Siblings keep mating among themselves hence the rate of deformities produced can be quite high.
Let them survive on their own. If you have several thickets of plants, rest assured that only the strongest will survive. This may be cruel but if you think of the future, there's no way for you to get rid of them and only a few lfs will take them considering they are rather too common.
Livebearer fry are, IMO, very easy to raise. Anything given will be appreciated.
In my case, I never keep livebearers due to the problems of overpopulation.
Well, not unless I have angelfish and tetras anyway to eliminate the fry.