I learned this method from an old-timer American by the name of Tex-Shooter in Slingshot Forum. He used 2 pieces of wooden dowels clamped together with rubber bands for the guide. I can't use rubber band on huge kitchen knives, so I use office clips instead.
I can consistently put a primary and secondary bevel on the knives. Split the bamboo chopstick half for a steeper secondary bevel, use whole chopstick for primary angle.
With this angle guide, all you need to do is apply pressure only on the edge area, not on the guide! I made this mistake when I was still experimenting. You can now forget about keeping the blade angle consistent, which is very tiring and there's always rooms for mistakes. During the finishing part on fine stone, you only need to focus on applying pressure on the backward movement, as taught in Korin videos. Sharpening becomes a breeze and you can casually hone the blade without paying attention to the angle anymore.
If the chopstick wobbles around, place your thumb on the spine to stop it in place.