I don't. I do have the rear draft inducer, but I don't use it. Our unit is 20 years old. I rebuilt mine last year. I understand your ideas about how it should work with the blower, but it cannot go into idle and burn cleanly. Thats where gasification boilers have the advantage. I know when the blower starts to kick off its about time for more wood. Think of it as an alarm, that way it doesn't go out. You talk about investing ductwork around a 20 year unit, I did. I reducted my whole home, with supplys and returns around the woodfurnace. I use my LP furnaces blower only, which has 2 leads on the r and g of the circuit board. By me running series, I eliminated the need to have dampers in the system. We have a 2400 sf home, w/10 foot ceilings. Its about 150 years old, but pretty tight. When its 20 out, I can have it 80 in the whole house within minutes. Our never goes out during the winter, 24/7.
The draft inducer makes people think that you can keep a house at a set temp with a furnace. Yeah right, those woodfurnaces need to dump the heat from the unit, or they will overheat quickly. I would think hard about the return. You can always use the ducting for a new furnace, just replacing a few pieces down the road.