There are many more on this site with way more roasting hours under there belt. I hope to see there comments here as well.
That said, I was trained as a roaster at a top roasting school in Vermont, USA. I have been roasting commercially for 1 and 1/2 years. Barely a newborn when it comes to roasting coffee.
As I remember we cupped every day after each roast to test our roast and find out how we did. In other words I think you have it backwards. We did not roast for cupping. Cupping was or is as I understand it a way to tell how you came out with your roast or a way to check green beans that your company is or might purchase for inventory.
Now if your talking about a public cupping to show off your coffees that you offer, I would roast the bean to it's optimal point to show off all it's varietal characteristics and flavor notes. Stay away from the dark side. You will tend to loose the best traits of the different greens you showcase..
Ambassador for Specialty Coffee and palate reform.
I think I've used wrong terminology, I meant to sample-roast in a quick and easy way like the barrel sample-roasters.
I have a new Diedrich ir3 table top (profile pic). If I'm not wrong you can roast minimum of more or less 450 grams. Anyone else with an ir3 experience?
...and thanks for the answers.