Smoke? *I havent noticed a great deal but I have a fan going while roasting.
Chaff, definitely. *Some beans more than others. I dont think you need to go the extent shown in the other thread. Another CS member nunu suggests a kind of sock made of flywire stuck on the end of the chimney.
My first roast was inside, near the backdoor, with a fan blowing chaff and smoke out the back door. It still triggered one of my smoke alarms. Does your unit have a garage? You might be better off roasting in it with the door open.
I dont think its worth trying the cooling mod. Dumping the roast into a colander or sieve and then cooling by fan is dead easy and probably stops the roast quicker.
I recommend trying several roasts using the tried and trusted methods before considering any mods.