Calculating Wire gauge?

No, more like about 22. Find the the cross section area in this chart for the awg and go up the same column to double the area. (I just found this chart with a quick search, and don't mean to recommend the website. It's just that this chart shows cross area and most charts online only show diameter.)

http://tnt-audio.com/clinica/awg_e.html

When you double up identical conductors, you gain appr 3 gauge sizes. As such, two 26 gauge wires would be equivalent to appr 23 gauge. To double that, you would need a total of four 26 gauge wires connected in parallel. This would give you appr 20 gauge. Each doubling of conductors cuts your series resistance in half, all things being equal. Sean
>

Oops, I meant 23, and I could have edited it if Sean weren't up at 3 am.