You want the integral of your function to equal the total load. Just visualize how your load function will be distributed among all of the nodes (based on their geometric location) and they all need to add to the total force applied.
Excel an be used, but Wolfram Alpha has a great online tool that does calculus (among many other awesome things). For example, for a total force of 100 lbs on a 2" diameter cylindrical hole, F0 = 59.42, as shown here: http://m.wolframalpha.com/input/?i=integrate+59.42+*+cos+x+dx+from+x%3D-1+to+1&x=0&y=0.
This method uses @stadlerj’s approach of splitting the cylinder in half, and applying this load to the surface on which the load is applied. Using my math, the cylindrical hole in question would need to be centered on the X-axis (assuming “x” is the independent variable).
You can double check your work in FEA by post-processing the reaction loads.
Does this make sense?