Neuter him. It may help the marking issue, and it certainly decreases his risk of some life-ending diseases.

I like the spray-bottle idea, but just with water.

If all else fails, I'd consider a dog behaviorist. Sounds wacky, but we used a guy that was magic. We adopted a cat-aggressive pitbull, and at the same time a stray kitten wandered into our home. Within a couple hours, he took the pit from a crazed cat-killer to the kitten's best friend and protector.