Not sure what you mean by size. The hole size doesn't really matter, as long as you cover all the leca with the screen so that your dirt doesn't fall through.
The too many babies- I was overrun a while back. All my frogs were laying eggs like crazy and it was getting to be a little too much. I had like 60 frogs and not enough room, lol.
My darts: Leucomelas, Azureus, Powder Blue, Man Creek, Bastimentos, Trivittatus, Terribilis