Sorry, but I have to disagree with this statement,
I used a double run of 10 AWG, which is the equivalent of 4 AWGFor equivalent wire gauge of a double run using same wire, you double the cross sectional area, not the diameter. Looking at this wire gauge chart, a double run of 10 AWG is equivalent to 7 AWG, and this AWG calculator confirms that.
Hope this helps with you future calculations.