I love my HotTop Progammable Coffee Roaster $930.
I set the timer for 20 minutes, set my kitchen timer for 18 minutes, then come back when the Kitchen timer goes off, and watch the last few minutes. I make sure the roast in the 2nd crack(steady cracking sound, that is different from the 1st crack) and then I push the dump button. Please check each roast for a black or over roasted bean, might be one or two, and discard them, one black bean can spoil your cup.