Indeed, if you use GE, use the I not the II. Look for one that says "windows and Doors" usually in a predominantly blue labeling.
The other question here is whether you need to add some bracing in order to affect a fix. It depends on the nature and size of the crack as well as it's location. Just covering it with silicone is not likely to be sufficient.
Join a fish club. Don't have one in your area? Start one.