Decal strips can be taken off in a few ways. There is a 'eraser' that you put on a drill that takes them off. You can use a heat gun or a hairdryer to get them off most practically. But if you're taking the paint down to bare metal, a sander will take them off as well.
I think Branda has the stripe dimensions on their website, the stripes aren't consistantly the same width over the whole car, they get wider as they get towards the roof, but the width between stays the same. It's an optical illusion that they are the same width, if you did do them the same width, they'd look like they got skinnier at the roof and windshield base. The factory painted on the stripes, whereas the rocker stripes were an adhesive tape. I've seen the double stripes in vinyl and I've seen the rockers in paint. If I were spending $4k-$5k, I'd want them in paint.