Additional problem to consider. If you've used any RainX product on the exterior glass in the past few months the repair won't hold. Most repair places (of any quality) will ask you that before starting to work on it. Within a short time the crack will start to spread again. I learned this the hard way
I've used RainX in the past, but it has been some time since I used it. Probably at least 4 months. Hopefully I am in the clear.