I have a 10 foot by 6 foot aviary. How many budgies can I keep in it?

I am building an aviary with my father-in-law and we are trying to figure out what we can keep in it. We are interested in Budgies because of their great colors and human interaction but are unsure of what an appropriate number would be in an aviary that size. We are also interested in finches. I know finches and budgies don't do well together in a cage but would they be okay with that much space to get away from each other? Thank you.