Pretty good video guys. I have a JD D120 which I service myself. To help facilitate oil drainage, I will roll the left side wheels onto a couple of small pieces of 2x4s. Before installing the new plugs, I verify the gap. Yes, the plugs are usually pre-gapped at the factory, but it is always safer to verify. I also put a little anti-seize on the treads which make them easier to remove next season. I always keep a few cans of inexpensive brake cleaner in my garage. This is great stuff for cleaning the oil filter port and small oil spills on the frame. I could not help but notice you did not balance the blades. Lawn mower blades spin at over 200 mph. If they are unbalanced, it can lead to excessive vibration which in turn can lead to other problems ranging from the loosening or breaking of bolts to engine damage due to stress on the blade shaft and spindle. Part of the servicing also includes greasing the front wheel spindle, wheel hub, front axle pivot, blade brake pivots, deck idler pivot and blade spindle. You guys have started a good thing, you just need to focus a little more on some of the details, especially the ones that relate to safety.