Hi Richard,
We have always used .11's for spraying sealers and stains(with a 1 gpm pump). However, Graco makes a fine finish tip that will greatly reduce overspray. A .210 fine finish tip will only produce a 4 inch fan.
But, you will have much more control and it will still be a whole lot quicker than a brush and roller. Before I started pressurewashing full time I was a painter for 18 years, so I will be more than happy to answer any paint related questions.