Just a sheen of it on your fingertips is plenty, and then simply handle the cases - just as the guys above said. If you actually see the stuff on the case, you are using way too much.
For inside the neck, it may not be ideal. But it can be used. Swipe your fingers as above, then pull a nylon bore/neck brush through your fingertips. Once. That's enough.
By the way, if you read the tub label, it says it's also good for leather. That brings me to the conclusion that it is more or less identical to Mink Oil paste. If so, it's largely anhydrous lanolin, plus a wax and/or oil as active ingredients. I've tried Mink Oil as case lube and it is indistinguishable from Hornady Unique.
