Bob,I would go with any extra horsepower you can get. ;-)
Bob question: Waxing the machine (wax what, any special type of wax)?
I just use an automotive car wax (some people use Pledge spray).
Bob question: Lubing the chute (with what)?
Some people spray LPS-3 in the chute, and I have heard of using silicone spray. I do not use any, but at the end of the season I’ll re-paint or spray lithium grease in my Honda's metal chute.
Bob question: Running the impeller before shut down (does this need to be done each time, how long)?
I think the main thing is not to have your impeller be jammed with snow or slush, and having it freezing up on you.
My new machine tips: extra shear pins/bolts, correctly adjusted skid shoes, and scraper bar, never-seize the impellers and augers, never-seize the wheel axles and I also like to have a yellow headlight on my blowers.
Good Luck,
John