To rip logs in half I simply did it by eye, which really was quite easy. Ripping boards is a completely different thing however.
I first flattened the top of the log a bit and then snapped a line for the first cut and also snapped lines for the other cuts.
It is very difficult to keep the saw perfectly straight. The slightest deviation from vertical results in a board thinner or thicker on one side. I struggled with trying to get the boards the same thickness when I first started, but did get better as time went on, but never perfect of course. Every board varied a bit.
I have used a ripping chain in the past but for this job I used a conventional chain for everything. Although slower, I did feel as if I had more control over the cut, as well as being able to crosscut the pieces to length as well as other cuts without needing to have two saws on the go.
I really didn't use any special technique in ripping. It just takes time to get a feel for it to end up with something usable versus firewood.
I took my time and concentrated on keeping the saw bar as vertical as possible. Not perfect by any means