Hi 'genesis
That sounds like you are off to a good start then.
If you find new corys now, they might be too young to participate in a spawning right away, but they will probably cause no harm. C. aeneus are not usually egg eaters and if they were, I would suggest waiting. I have young ones in some of my spawning tanks and it's just fine. When the time comes for them, they will join in. It will also do them good to have lots of extra food to eat while the others are being conditioned.
I spawn my corys in 10 gallon tanks and when the parents have finished laying their eggs I move the adults out and clean the gravel or sand out too. This leaves a clean tank for the fry to grow up in.
To begin conditioning, start feeding them heavily on live blackworms or tubifex worms or on frozen bloodworms. Give them all they want to eat, but if you feed the frozen foods, be sure that any they don't finish are removed as soon as you're sure they don't want them. Live worms will sink to the bottom and be there when the corys want to dig them up, so they are not a problem. You'll probably want to do this for about two weeks, especially if it's their first time.
During this time I like to keep the tank at around 75 degrees F. Then, when I think they are ready, I just do a big water change and turn the heater off. They will usually spawn in the next few days.