Have you tried the Ethiopian Harrar? That’s one of my favorites to roast. When brewed right after roasting, it has one of the most complex (and pleasant IMO) flavors of just about anything else I’ve tried.
I haven’t roasted coffee in about ten years, but I recall that beans from Sumatra and the Dominican Republic were my favorites. I’ll tell you something else that is against all advice any coffee roaster will give you. You are supposed to let the hot beans quench on a metal or ceramic tray after roasting. But you’ll see the fresh-roasted beans smoking as they quench, and if you pass your hand over them, you’ll detect a fine oily residue on your skin. As the bean cools, more complex flavors are supposed to develop, but, then again, something else is lost. Sometimes I would take the hot beans right from the roaster, grind them, throw them into a French press, and pour boiling water on top of the smoking grinds. The grinds would jump and hiss when the water hit, and then everything would swirl around and develop a thick caramel colored froth. By all rights, it should not have tasted good, but it was unbelievably tasty.
It can be hit or miss, but when it is a hit, oh boy is Harar awesome. I still remember my first cup, at (ironically) a Starbucks where they brewed me a cup in a french press. I’ve never seen them carry it again.
I can’t recall exactly when that was, I’m guessing 1993-94.