I use that, but it’s not homemade. I forget the brand, it’s got a sort of bellows on one side, and that pumps the solution up to where it can do the most good. Either way (commercial or homemade) one big benefit is to wash out the dust and allergens.
So long as the exit is funneled, gravity gets the saltwater into the sinuses. You can use liberal amounts if it’s home made, and you can also make sure that it’s sea salt. Only drawback, a low level of salt and no preservatives means that the salt water will spoil over time. It’s a good idea to rotate two dispensers, one being sanitized by the sun. It’s also helpful if the dispensers are clear to help see spoilage.