So, i'm now using an external blower (small mattress pump) to increase airflow through the I-roast 2. It gives me the same degree of control as restricting airflow did, but produces a superior roast to even the unmodded i-roast. Rather than direct airflow in one vent while taping up the rest (it was difficult to get a good seal on all the holes - screws, buttons, etc), I placed the bottom of the iroast in a ziploc bag and taped the bag around the midpoint of the roaster. Now the pump blows air into the bag, which results in very little loss (most of the inflow air goes through the roaster). I set the roaster to 15:00 at the highest temp - 485 i think - and manually control fan speed with a light dimmer that i spliced into the wiring for the air pump. The iroast doesn't give me 485 right at the start of the roast, because of the built in electronics, but eventually i get a usable and adjustable range of temps to work with. Next up: enclosing the fan and base of iroast in a box, mounting my dimmer to the box, and also adding a thermocouple to monitor bean temp.