Big 4 Pattern Back Zippers on Tops

Confident beginner. Just not a lot of experience with zippers.

I've been buying Big 4 patterns, but a lot of the tops I buy that are fitted have full zippers in the back.

I don't have a ladies' maid, and I know there are these bracelet chains you can buy to help you zip a back zipper, but can't I just put this zipper in upside down and not make it go all the way up the entire garment?

I have a Reformation top that has an upside down zipper, and it leaves a few inches at the top where it's sew together so that the top never totally comes apart.

Is what I'm describing a huge skill leap beyond how McCall's has these tops designed?

I bought a big pack of random zippers and I was going to practice with a few of them first.