I have quite a bit of plants in my community tank and all but one fry survived. Both females have gone through once each...
So this time around, I placed one of the female in a separate 10g tank with a sponge filter. (I expect her to deliver in about one week based on the last delivery date). Hopefully, I'll have a better survival rate than 2% this time around...
From what I have read, platy females produce hormones where they will loose the tempation to eat their own fries for about 12 hours. (Could someone confirm?) If this is true, I can check every 12 hours and keep most of the fries alive...
They will probably be fine in the 29 gallon as long as they have little hiding places.
As for feeding, a little hard boiled egg yolk goes a long way. It is pure protein. Of course it is messy and the adults will want to eat it as well. I have just been feeing Hagen's food for live bearers as it is really tiny mixed flakes. My fry have been able to get enough to do well and I just feed the once a day that I normally do.
Another good food for baby livebearers is Hikari micromini and their fancy guppy food. The adults gobble the stuff down too. Its cleaner than mucking with egg yolk and cheaper than baby foods like Liquifry. The babies will grow quicker if they don't have to compete with their parents for food.
If you don't already have some, hornwort is a nice plant to toss in with babies. It gives them good cover and they like to pick at it. Plus it's cheap and grows fast
I've heard the hormone rumour before, but none of my livebearers ever did! The only one I've had the didn't scarf down their own kids are my Endler's.