That's going to be a bit tricky. By convention a console window is 80 characters across so that part is easy. But the height isn't standardized. You could set the console windows height, but you would have to let us know what platform you are working on.
Getting off of DOSBox would be mine. Seriously, just for my own curiosity, what arbitrary reason are you using to justify the need to run on a 20 year old platform? My guess is that making your product look pretty is meaningless. Your grade is going to get thrashed for requiring an emulator.