Sprayers should only be stored and shipped upright. Sprayers contain a vent that allows air to flow into the bottle which prevents vacuum lock.
Closure sizes are expressed using two different numbers.
For example, a closure size of (20/400) has a diameter of 20 mm and fits a bottle with a 400 GPI thread finish.
Some neck sizes are interchangeable. For instance, a 20/410 closure will usually fit on a 20/400 bottle. Also, 410 and 415 are usually interchangeable if the closure is not tamper evident.