Well I guess i missed the fun.
The rheostats are for the convection blower and the stoker motor (the lower one is stoker and the separate one is convection). The problem with running the stoker motor on the rheostat is that the combustion fan is also run by the same motor and it will not turn fast enough to provide a good fire at low speeds. So my way of doing it with out modifications is to run the stoker at full speed and adjust the stoker stroke to acheive the desired heat output.
Of course the real solution is to remove the plastic squirrel cage from the stoker motor, install an external combustion fan and run the whole thing with a Coal-Trol from the nice folks at Automation correct.
As already suggested, if the stove looks OK and is less than $1000 buy it! You can't go wrong, it will pay for itself in a couple of years and you will be able to sell it for more than you paid if you take care of it.
I left you a message on your phone, call me any time, I can help you get it hooked up. I also have a scanned copy of the manual I can Email you if need be.
Now run out and buy that stove!