Here's a basic guideline with diagram.

Here is a link that might be useful: Making Sense of Kitchen Faucets

Thanks rococogurl for responding. I have gone to that link and the quality on my monitor isn't good. It's pretty fuzzy. Plus, I have an offset drain and the link is for a traditional mount with a centered drain.

The drain location honestly does not matter as all sink have a slope to drain. Select the faucet that you like from a aesthetics and functionality perspective. The drain location is another variable that will just add confusion. Good luck!

I thought the rule of thumb was to have a spout reach that when water flowed, it flowed into the drain? I know I am not going to do that with an offset drain and a faucet mounted in the middle of the sink, so should I just calculate a reach as if the drain were in the middle? What height is good for a farm house sink that is about 2" above counter mounted and is apprx. 8.5" deep?

I had heard that 'rule of thumb' too AFTER I had bought my sink and faucet. For a second, I worried about it, but when you think about it, WHY would you want all the water running down the drain? The object is usually to fill the sink or a vase or a pot... As GWlolo said, all sinks are designed to slope towards the drain, as for height, think about the size of pot, vase or whatever you want to fit under spout. I am a gardener, and I could hardly wait to be able to fill vases from the spout!

Play mock-up as the new faucets now seem humongous! With cardboard roll up a fake faucet and see what dimensions you like and is proportionate to your window, sink, etc....

And for for those of us with double sinks, well, I guess we would have a left off-set AND a right off-set drain!