Aviary with a cockateil and lotsa budgies!!??

Hi everyone. I am soon to set up a large outdoor aviary (wood and mesh) and i plan to keep 15+ :?: budgies in there with a couple of cockateils. How big will an aviary to contain these birds need to be?
Will cockateils and budgies live happily together? I have read that cockateils are extremely tolerating of different species but i am not so sure about budgies. If this combination would not work, could you offer me an alternative?
Finally, providing the conbination of species is ok, what sort of environment would i need to create within the aviary and what equipment would i need to keep these birds happy and healthy?

 

Hi i have an 8x6ft shed with a 8x6ft flight that was used by my budgies aswell as my cockatiels.

Cockatiels are very tolerant of other birds but budgies are very agressive when mating if you have next boxes in the aviary the budgies will actually invade a cockatiel nest and either smash the eggs or if there is chicks in the nest they will kill the chicks.
So a watchful eye should be kept on the birds and them all checked regulary for any signs of fighting

mike