We have tried all kinds of paints and stains and australian timber oil from sevens is by far the most durable product for decks, Imo.
We always pressure wash the deck a week before a dry spell so the water can dry. Then just sweep it and spray the oil on with a garden sprayer. A helper with a piece of cardboard as someone mentioned is a plus.
I dont like using a hvlp or other gun because you are always dragging the hose behind you and it is easy to mess up your fresh work a dirty hose.