dynasty salary cap

Thanks to Terry's thread on the subject, I've learned how to edit the salary cap in dynasty mode in order to make it more realistic to today's numbers. But since dynasty mode doesn't account for paying luxury tax or other aspects of the CBA, I was wondering which level should I set it at to be most REALISITC. Should I go with the 2009-2010 salary cap of $57.70M or should I go with the 2009-2010 luxury tax level of $69.92M? Thanks in advance for your thoughts!

Current salary cap. If you set it to the luxury tax threshold, teams will have more cap room than they realistically should.