[Zeke]

The pump sprayer to transfer the stain is not such a bad idea, but you should follow up with a brush. You could also get a pressure roller, but you won't get the edges and corners. Actually, a combination of tools always works best. When I do an iron fence, I use a mini roller and a detail gun for the tight spots. I'll have a brush wet as well.

When I spray stucco, I back roll with a roller. Letting the paint just lay on the surface is for very smooth surfaces, not so much for wood or any porous material.