I find it difficult to switch back and forth so I shoot with both eye open, especially when hunting or using RedDots. I suppose I'd go to closing one eye if I started shooting competition. Whatever technique we use, it comes second nature and really give it little thought. .....
As far as adjusting for clarity, you have focus and then sharpen the image of both radicles. I usually look away then look again to see my results. I repeat the process and routinely look away so my eye isn't trying to compensate.
Be Safe !!!