You would have one circuit with two leads off of one breaker, not two circuits.Like I said wait for the pros. I think on those square d panels you can run two circuits on one breaker
Thanks. What's easier? A new sub panel or replace the current one? How do I best estimate my current load since obviously not everything is in use at the same time?Holy double stabs. You're full. Start a new sub panel off your main and move some stuff to the new panel. Check your loading as well and make sure you're not overloading your panel