Hello Robert and all others,
Thank you for your participation in this thread and your comments. I hope this topic will be helpful not just to me but to other people too. Especially I would like to thank Robert for his detail description and interesting video. I am surprised how precisely you are marking your logs with marking knife. It seems to be a Japanese furniture and not part of roof. :-)
Robert, I share your philosophy. I know there are probably a lot of other ways that could be cheaper or faster. But I like naturally-shaped logs as well.
I couldn't understand what you measured in pictures with bubble-level because I thought you need just measure angle between board with cut-outs and horizontal plane/side line on the log as you described in method 2 points and angle. It is much clearer now.
If I understand your 3 point method, you are looking for logs with same horizontal diameter. And if there are differences in vertical diameters you'll find intersection point of both logs by drawing their shape onto board and find their intersection. So the angle of joinery plane is not exactly 22.5° (=45°/2, the bigger part of joinery) but slightly differ depending on log vertical diameter differences. It is great idea!
And it is really nice how logs are connected without any gaps and overhanging. If there are not any bumps and knots the log surfaces are smoothly connected. If there are bumps the logs are smoothly connected at least in both HP and both points where vertical plane meets log surface (I mean points of crossing of upper chalk line on the beam log with upper and lower chalk line on rafter log).
You have a big advantage you can choose from a lot of different sizes logs, different shapes and diameters. Unfortunately I have limited supply. If I have problems to find the right logs for such joinery I hope there is another solution. It's not the same philosophy, but it could be helpful. I mean adjusting just rafter log shape to flat/square shape. And leave the beam log untouched circular. The same way is done
this or
this joinery. It is not so nice but it could solve my problem with different log sizes. And the way how to transfer lines and angles onto log is probably similar but more difficult.
If someone has any other ideas I'll appreciate them.