I played around with these techniques for an hour or so today, just cutting marginal logs that had been lying on the ground for too long. A couple of 12” alder logs about 5’ long and a bigger 8’ cedar log.
I was just experimenting with it and not trying to make anything worthwhile, but the cuts actually turned out surprisingly good. Not as nice as with a mill, but much closer than you would expect.
I found the best guide to be a straight piece of lumber and the best technique was to make the cut right alongside it. If you use the rear handle to do almost all the guide work left to right and let gravity keep the cut vertical, it really does do an excellent job of making parallel and vertical cuts.
What I kept screwing up was that as I drew the saw through the cut over and over again inevitably I would wander just a little bit left to right and that would cause ripples in the cut. Also, the deeper you make the cut the harder it is to sight along the bar and keep it perfectly lined up. I was using a 28” bar for it today. I’ll try a longer bar when I get the chance.