I saw a person spray house with a wagner. Got paint on soffets, windows, doors, block, even shingles. Over spray will be a problem.
I purchased a wagner 2 stage pump sprayer. Put hose in 5 gallon bucket and go to work. Used it to paint the inside of new construction. No carpet, doors, plastic over windows. Never again. A roller on drywall has texture, sprayer doesn't. It looked like a snow storm when I was painting. NO THANK YOU.
I had to paint very old aluminum siding the paint fell off. It had hail damage, dents, holes. Used painters caulk, filled the holes and dents. Many applications. Went to menards and got a special paint for aluminun. I wanted a flat textured finish to hide my work. Rolled it on and no problems. Might consider putting something in the paint to prevent mold too.
Knew of a guy that filled pellet gun holes with JB weld and sanded. Then rolled. I would not recommend spraying, a flat, gloss reflective finish will show all the sins in the siding. George