That high of ABV, your yeast is stressed. Either add more yeast to each bottle, like you're suggesting, or wait longer. I brewed a batch of barleywine last Dec. 12%, added yeast when I bottled, cracked one open three weeks into bottle conditioning, perfect carbonation.
And yes, US-05 would be perfect for this. That's been my go to yeast for a while. Nice and clean flavor.