About to start a remodel on a 1800 square foot 3 br house with a 200 amp service. Need to add 2-4 circuits to the main panel as the sub panel will fill up. I have a about 60 foot run from main panel to the first junction boxes and am concerned about voltage drop. The feed will run through a very accessible attic and I could use 10-3 for 2 circuits, install a labeled and accessible junction box in the attic and then run 12-2 to complete the job. Is this legal and a decent idea? Job will be inspected. Thanks for any input.