Setting up lights/cameras with motion detectors will go a long way in deterrence. That means you won't be shooting people who would normally surrender right away. Most people are easily deterred, and that is the best solution.
There are always some you need to worry about, but you have to weigh the risks to the rewards of dealing with intruders. I agree that you need to check out your local laws first. Find out what rights you have. The biggest thing here is, it sounds like your business isn't on the property where you live. That changes legal rights.
I'm not saying don't defend what is yours, but don't go to jail for doing so either.
Also, take self defense classes. They are worth every penny, and remember to practice with your firearm. It may seem stupid, but it's not. Getting into any situation with the adrenaline pumping changes the dynamics immediately.