Plant Advice Please

[Johnsontanks]

I am just starting a planted tank and plan on using the diy co2 system. How many plants should I have before I start the co2? I have one in each of my 5, 10, 20H tanks. I have baby tears which after I bought it they said they are really hard to raise. ugh I want to have several plants and no more plastic ones so I want to do it right. I also have Iron drops and plan on getting flourish to put in the tanks too.
another question too, should I run an airstone along with the diffuser? I am scared the co2 will be too high especially in my 5 gallon.
thanks for any and all help.
Johnsontanks