When you're doing hamaguriba then you should flatten secondary bevel and then start primary bevel in 1/3 of height between shinogi and edge. This is really hard to achieve for me because I had to keep very low angle. I raised the spine a liitle bit, cutted new adge and then I lowered the spine. I've noticed that it was much easier for me.
The widest bevel I could achieve.
This is a picture where blade road is finished on JNS 1000 stone and edge is polished on White Binsui. You can see that I have settled new edge on lamination line or place where soft jigane and hard hagane meets each other.
I tried many things to polish the blade even more. When I used aoto mud and ultra hard felt and polished the blade I couldn't reach actual edge. Then I tried to make some experiments and I ruined it again. I tried some fingerstones mud, stones mud etc. I have only scratched it even more. However I can't work on it more because I hardly used that knife and already removed lots of steel. To finish it I've used paste made out of chromium oxide to polish the blade a little bit.