The term "pinstripe" has nothing to do with solid back striping or anything else other than that the animal displays the gene. Pinstripe refers to the codominant gene named pinstripe, not a vocabulary term used to describe a whimsical happenstance of pattern, like the terms "black back" or "full stripe". "Black back" and "full stripe" occur naturally, often randomly, and it doesn't mean there is a gene behind it (though there are some genetic black backs and full stripes, most aren't). It's just a cool pattern abnormality, if you can even call it that.
"Pinstripe" is always going to be used in reference to the codom gene that can be passed on, whether the animal has a full back stripe or broken one, busy or random pattern, etc.