Finding the Right Coffee Grind I just purchased a burr grinder to use with a chorreador coffee maker. A chorreador is functionally similar to a pour over, but the cloth filter will likely have different characteristics.

I've read that the grind should be "fine to medium-fine", and I imagine the specifics are left to taste and depend on other characteristics (roast, amount of beans, etc.). I will tune my grind based on some experimentation, but what are the characteristics I should be looking for? In general, how does coarseness or fineness affect the coffee profile? What characteristics should I expect to vary?

Are there particular characteristics that are "bad" and I should tune to avoid (for example, I've heard the silt in coffee can be hard on digestion)?

I'm not looking for an answer to "how fine should I grins my coffee?", but rather what are the parameters I should look for when experimenting with the grind?
In short, it's about extraction.  Too fast, and you don't get the right flavours and too slow and you'll get off and bitter tastes.

With a setup like the one you describe you can't change the speed the water passes through coffee (unlike espresso, for example) so you control how long water spends with your coffee (and the surface area of contact) by the size of the grind.  

The water will tend to stay and mud up super fine grinds.  If you were to try to filter through turkish grind, you'd be waiting a long time and might taste something harsh.

Too coarse of a grind and the water will run through and not pick up enough (low extraction).

Aside from colour, taste and aroma, what you are looking for is how long it takes for water to pass through the coffee grind.  I can't tell you how long for your specific setup, but if you're going slower than 20 seconds per ounce of water, it's likely too fine of a grind.  Also note that the longer water spends with coffee, the more caffeine it'll pick up.

Finally, if you can, keep an eye on the drips as they leave the filter.  When the drop or stream is no longer cloudy and starts looking clear, that's about when you've extracted what you can with that grind (both amount and coarseness).