Thanks for posting the video up Col, works great in practice.
As Grayorm mentioned, tap a wedge or two into the starting end of the cut as you get to around a third or quarter of the distance left and it will take the pressure off the chainsaw bar and make it easier for you to push towards the end otherwise the weight of the plank will pinch the bar.
I expect you know this already too, but when filing the chain sharp make sure to file the depth limiters behind the teeth a little bit too so the chain continues to have enough bite at the teeth.
Other than that I think the next improvement could be putting some wheels on your stool and getting the missus to push you and the saw along from behind :lol:
Great job Col =D>
Cheers, Paul