I've been quilting for about fifteen years now and up until about a month ago, I almost always pressed my seams to one side. Then out of the blue, I just decided to start pressing them open - wow! I have noticed such a difference in my precision. It's not that it was bad before, but it's definitely better with pressed open seams!
Also, I find FMQ to be much easier with open seams.
I don't personally see the need to double stitch strips, but you do what works for you Carol.