Considering the cost of copper, etc., the materials cost of your project are not exactly cheap but the labor is probably more expensive. It will be easier to run both lines at the same time, which should reduce your labor cost compared to running one and then deciding later you should have run two. I have three dedicated circuits to my audio area and all three are on breakers next to each other on the same side of the panel. I do not regret using 10awg wire, even though the circuits are each only 20A.
