I rock the saw sometimes when the chain needs sharpened and I have some imaginary goal in mind before I stop to sharpen (finish this cut, finish this tank of fuel, etc) changing the chains angle of attack on the wood seems to help it cut better is this scenario...in the perfect world, holding the saw steady obviously makes the fastest cut though.
Hey Dave - You asked a real good question. If you are bucking big logs (relative to your bar's length) on rolling ground, you buck the downhill side first (over-bucking) if possible by reaching over. That lower far quarter of the log becomes no man's land - when the log gets bucked and then shifts or rolls. You want to rid yourself of that far bottom wood early on because you do not want to have be on that side or underneath the log reaching for it when finishing your cut. Then rock the saw back staying nice and lined up in the kerf you just cut to work your side of the log (the uphill side) so you can get yourself back down on solid ground and finish your cut (be that either up or down) depending on how the log is tensioned or compressed. And live to do it all again! Here's an 38 second example, sort of, but he's 3/4 through when the vid starts: Or, watch Bjarne Butler be forced into bucking the downhill bottom quarter (from underneath it) on a big Cedar stick at 5:45. Or better yet watch the whole video - this young man deserves much respect.
I buck like that when the bar length is close to or shorter than the log being bucked. Lifelong cutting habit that works fine for me. Most of my cutting life i ran only a 16" bar so it was the norm. Of course i watch the nose so it doesnt hit the ground. I will section and roll with peavey if i have it with me. Now with multiple saws and 20", 28" & 36" bars i dont have to as often.
I'll over buck big stuff for the simple fact I can dawg in & keep my back straighter for longer. Once the far side of the log is cut with the saw standing vertical it drops through pretty fast on the horizontal plane. Less time bent over.
Rarely do I ever use a bar smaller than the wood so my method on larger stuff is to stick the dogs in so the bar is pointing up a fair bit as it starts cutting. When I'm in far enough I quickly stick a wedge in with a couple smacks from the hatchet while one handing the saw then stick the hatchet grab the saw and go straight down. About a foot from the ground my boot knocks the chip pile away and I keep the gunning sights vertical and hit the ground. Basically leaving the bark at the bottom. No rolling. Typed out it seems more complicated than it is. And I know the safety police don't like one hand cutting.